Modernity and black magic can coexist? 1. In Buddhism, does black magic, magic spell exist? If it is, what's our belief system should be when we are taught to treat all with loving kindness?
Often Black magic is not only concerned with negative, evil, demons, or bad things. Black magic spells and amulets can also be used for good, protection and as many other uses as there are human needs and desires.
Thailand being the predominately a Buddhist country, but this tends to be mixed with older animistic beliefs and some of them also have a strong belief in powerful supernatural entities.
Thailand is indeed one of the top tourist spot but some people also avoid going due to the fear of all these.
I for one, love Thailand a lot and been there many times but often curious about all this and at times confused.
I have read somewhere, some of the the top Monks in Thailand are that spiritually powerful to perform all these.
2. Supposingly all these exist, what's the odd of being the target apart from jealousy?Supposingly if you are very much enlightened and practice meditation vigorously, does this make you any less of being the target?
As some of the victims can be severely disturbed emotionally and in some cases it might even lead to death.
In Buddhism, does black magic, magic spell exist?
I believe so... the Buddha seems to recognize some pretty powerful black magic, e.g.:

“What do you think, householder? Suppose some recluse or brahmin came here possessed of supernormal power and attained to mastery of mind, and he spoke thus: ‘I will reduce this town of Nāḷandā to ashes with one mental act of hate.’ What do you think, householder, would such a recluse or brahmin be able to do that?”
“Venerable sir, such a recluse or brahmin possessed of supernormal power and attained to mastery of mind would be able to reduce ten, twenty, thirty, forty, or even fifty Nāḷandās to ashes with one mental act of hate, so what does a single trivial Nāḷandā count for?”
-- MN 56 (Bodhi, trans)


If it is, what's our belief system should be when we are taught to treat all with loving kindness?
I don't believe this changes our imperative to treat all with loving kindness...

&quot;Monks, even if bandits were to savagely sever you, limb by limb, with a double-handled saw, even then, whoever of you harbors ill will at heart would not be upholding my Teaching. Monks, even in such a situation you should train yourselves thus: 'Neither shall our minds be affected by this, nor for this matter shall we give vent to evil words, but we shall remain full of concern and pity, with a mind of love, and we shall not give in to hatred. On the contrary, we shall live projecting thoughts of universal love to those very persons, making them as well as the whole world the object of our thoughts of universal love — thoughts that have grown great, exalted and measureless. We shall dwell radiating these thoughts which are void of hostility and ill will.' It is in this way, monks, that you should train yourselves.
-- MN 21 (Buddharakkhita, trans)


2. Supposingly all these exist, what's the odd of being the target apart from jealousy?
I don't think this question is relevant to our site.

Supposingly if you are very much enlightened and practice meditation vigorously, does this make you any less of being the target?
Maybe... to some extent enlightenment protects one from harm, but mostly it protects one from reacting to harm and therefore causing further retribution. The stories of Angulimala and Mogallana both exemplify this idea.