so many controversies!πŸ™„ why shouldn't I give my kid Tylenol?

I don't understand what I'm supposed to doπŸ˜‚πŸ™ˆ
Being a mother is already hard and then you get told 1,000,000 things to ABSOLUTELY NOT DO!Β 
What's wrong with Tylenol now? Why am I being told not to use it?