Muhammad ibn ‘Abd al-Wahhaab – a reformer concerning whom many malicious lies have been told
Question

Why is so much of what is said about Shaykh al-Islam Muhammad ibn ‘Abd al-Wahhaab so hostile, and why are his followers called Wahhabis?.
Praise be to Allah.You should note that one of the ways in which Allah deals with His chosen slaves is to test them according to the level of their faith, to show who is sincere and who is not. Allah says (interpretation of the meaning): 
“Alif-Laam-Meem.
[These letters are one of the miracles of the Quran, and none but Allah (Alone) knows their meanings.]
2. Do people think that they will be left alone because they say: ‘We believe,’ and will not be tested.
3. And We indeed tested those who were before them. And Allah will certainly make (it) known (the truth of) those who are true, and will certainly make (it) known (the falsehood of) those who are liars, (although Allah knows all that before putting them to test)” [Al-‘Ankaboot 29:1-3]
Those who are most severely tested are the Prophets, then the next best and the next best, as it says in the saheeh hadeeth of the Prophet (peace and blessings of Allah be upon him). 
If you study the seerah (biography) of the Messenger of Allah (peace and blessings of Allah be upon him), you will see that he went through severe tests; he was even accused of being a liar, a sorcerer and a madman; garbage and filth were thrown on his back; he was expelled from Makkah; and his feet bled in al-Taa’if. This was the situation of all the Prophets who were rejected before him (peace and blessings of Allah be upon him). 
Shaykh al-Islam Muhammad ibn ‘Abd al-Wahhaab (may Allah have mercy on him) suffered the same as other sincere scholars and daa’iyahs, but in the end the message of truth that he brought prevailed. How could it be otherwise? How could the light of truth be extinguished? Think about this man and how Allah helped him to sow the seeds of Tawheed throughout the Arabian Peninsula and put an end to all kinds of shirk. If this indicates anything, it indicates that he was sincere in his call and made sacrifices for that cause as far as we can tell, and of course his efforts were supported and helped by Allah. 
But the enemies of this call have spared no effort to make false accusations concerning it. They claimed – falsely – that the Shaykh claimed to be a prophet, and that he did not respect the Messenger of Allah (peace and blessings of Allah be upon him) properly, and that he condemned all the ummah as kaafirs… and other fabrications and lies that were told about him. Anyone who examines these claims will realize for sure that they are all lies and fabrications. The books of the Shaykh which are widely circulated bear the greatest witness to that, and his followers who answered his call never mentioned anything to that effect. If the matter were as they claim, his followers would have conveyed the same ideas, otherwise they would have been disloyal to him. If you want to know more details about this and to clarify the matter, you should read the book Da’aawa al-Manaawi’een li Da’wah al-Shaykh Muhammad ibn ‘Abd al-Wahhaab by Dr ‘Abd al-‘Azeez al-‘Abd al-Lateef, which will answer all your questions, if Allah wills. 
With regard to calling his followers Wahhaabis, this is just another in a long series of fabrications made up by the enemies of his call, to divert people away from the call of truth and to place a barrier between his call and the people so that the call will not reach them. If you study the story of how al-Tufayl ibn ‘Amr al-Dawsi (may Allah be pleased with him) became Muslim, you will see the parallels with what happened in the case of Imam Muhammad ibn ‘Abd al-Wahhaab. 
Ibn Hishaam narrated in his Seerah (1/394) that al-Tufayl set out towards Makkah, but Quraysh intercepted him at the gates of the city and warned him against listening to Muhammad (peace and blessings of Allah be upon him). They made him think that he was a sorcerer who could cause division between man and wife… they kept on at him until he took some cotton and put it in his ears. Then when he saw the Prophet (peace and blessings of Allah be upon him), he thought to himself that he would take out the cotton and listen to him, and if what he said was true then he would accept it from him, and if he what he said was false and abhorrent, he would reject it. When he listened to him, all he could do was become Muslim on the spot. 
Yes, he became Muslim after putting cotton in his ears. Those who oppose the call of Shaykh Muhammad ibn ‘Abd al-Wahhaab fabricated lies the same way Quraysh did. Quraysh understood full well that the call of Muhammad (peace and blessings of Allah be upon him) had the power to reach people’s hearts and minds, so they exaggerated in their lies about the Messenger of Allah (peace and blessings of Allah be upon him) in an attempt to stop the truth reaching people. Similarly we see that those who speak against Shaykh Muhammad ibn ‘Abd al-Wahhaab and his followers repeat the same lies that were told against the original call. 
You should – if you follow the truth – not pay any attention to these lies and fabrications. You should look for the truth of the matter by reading the books of Shaykh Muhammad ibn ‘Abd al-Wahhaab, for his books are the greatest proof that these people are lying, praise be to Allah. 
There is another subtle point that should be noted, which is that the Shaykh’s name was Muhammad, the attributive of which is Muhammadi. The word Wahhabi is the attributive derived from al-Wahhaab (the Bestower), who is Allah, as He says (interpretation of the meaning): 
“Our Lord! Let not our hearts deviate (from the truth) after You have guided us, and grant us mercy from You. Truly, You are the Bestower [al-Wahhaab]” [Aal ‘Imraan 3:8]
As al-Zajjaaj said in Ishtiqaaq Asma’-Allah, p. 126, al-Wahhaab “is the One Who gives a great deal. This form (fa’’aal) in Arabic is indicative of something that is done to a great extent. Allah is al-Wahhaab (the Bestower) Who gives to His slaves one after another.” 
Undoubtedly the path of al-Wahhaab is the path of truth in which there is no crookedness or fabrication, and His party is the one that will prevail. Allah says (interpretation of the meaning): 
“And whosoever takes Allah, His Messenger, and those who have believed, as Protectors, then the party of Allah will be the victorious” [Al-Maa’idah 5:56] 
“They are the party of Allah. Verily, it is the party of Allah that will be the successful” [Al-Mujaadilah 58:22]
Long ago they accused al-Shaafa’i of being a Raafidi (Shi’ah) and he refuted them by saying:
“If being a Raafidi means loving the family of Muhammad, then let the two races (of mankind and the jinn) bear witness that I am a Raafidi.” 
We refute the claims of those who accuse us of being Wahhabis by quoting the words of Shaykh Mullah ‘Imraan who was a Shi’i but Allah guided him to the Sunnah. He said: 
“If the follower of Ahmad [the Prophet (peace and blessings of Allah be upon him)] is a Wahhaabi, then I affirm that I am a Wahhaabi 
I reject the association of any other with Allah, for I have no Lord except the Unique, the Bestower (al-Wahhaab) 
Those who were called by the Prophet accused him of being a sorcerer and a liar.” 
(See: Manhaaj al-Firqat al-Naajiyah by Shaykh Muhammad Jameel Zayno, p. 142-143. 
And Allah knows best.