Question: What I mean is that is it more dangerous than other contact sports that aren't martial arts? Such as Football, Soccer, Basketball, etc...

And if yes, why?

Answer: 
I'm not sure that your statement about the safety of boxing is generally accepted.

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> ["There is absolutely no way you can make boxing safe," said Nelson Richards, MD, a delegate from the American Academy of Neurology who proposed the original resolution to ban the sport in 1983.](https://www.ama-assn.org/amednews/2002/07/08/hlsb0708.htm)
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[The BBC reported](http://www.bbc.co.uk/health/physical_health/conditions/boxing.shtml)

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> According to brain surgeons, over 80 per cent of professional boxers have serious brain scarring on MRI scans. The evidence for harm or cumulative brain damage to amateur boxers is less clear.
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Boxing advocates point out that amateur boxing [has fewer injuries](http://www.boxinggyms.com/gladiator/newpaper/safe.htm) than soccer, gymnastics, etc. However that source doesn't cite how they measure "fewer injuries", and doesn't state whether they count long term damage to the brain. [There is some evidence that even amateur boxing can cause brain damage.](http://www.science20.com/news_articles/even_amateur_boxing_can_cause_brain_damage-89512)

Ultimately, you may want to look at a source which [compares injury rates](http://www.thecni.org/reviews/11-1-p35-gerberkozora.htm). A quick google search suggests that [football and soccer](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2267335/) have the highest injury rate/hour practiced. But that doesn't address the severity or long term consequences of those injuries.
While black eyes and minor bruises or the occasional broke nose are quite common in boxing, i think the devastating injuries like cruciate-ruptures are rare.

From my non-representative experience i'd say that runners, soccer-players and the like usually spend more time with doctors because of knee-injuries or broken ankles than (thai) boxers.

Boxing happens in a very controlled environment, there is only one opponent to pay attention to and the attacks and defenses are well-established. While there is a big strategic component, there is not much creativity going into making up moves on the fly.

Soccer for example seems much less predictable to me. While running at full speed an focusing on the ball one may have to deal with being tackled at any moment.