Almost all my life I've absolutely despised children. Pretty much from the moment I stopped being a child I've hated being around children.
It doesn't even matter what the child is doing. Whether they're laughing and having fun or screaming and throwing a tantrum. The sound of a child being loud activates an almost primal rage that I can barely contain.
I've had to leave social gatherings/restaurants/grocery stores all because if I'd stayed I'd have made a complete ass of myself by screaming at a child just for existing.
It's even worse with infants which makes me feel horrible because I know they can't help it. I know the kids don't know any better and it's our job as adults to get them through childhood, but my blood boils when they get loud or demand attention.
Has anyone else dealt with something like this? Is there anything I can do to stop from getting so angry?
I think the OP clearly doesn't like that they have this reaction (as someone else pointed out, and as you acknowledged). I think I understand why you might think this came from a lack of empathy. You like kids, what could be wrong with them acting like kids do? Sure, they're loud, but it's not that big of a deal! This person must have no empathy, because if they did, they'd be fine with it. People with no empathy are psychopaths, so OP must be a psychopath.
I think you're already starting to see what's wrong with that line of reasoning, which I really appreciate. Just to restate it here, the OP probably doesn't hate children, they just have problems with overstimulation (possibly misophonia or autism spectrum stuff). Not everyone has experienced overstimulation, but I can assure you that at best, it makes you reaaally cranky. Feelings of rage aren't surprising to me. If the OP wants, there are coping strategies and things they can do to help themselves in certain circumstances, but they're not wrong or bad. Their brain just works differently from other folks, and this is one of the effects of that.
It's not society's job to fix this (because kids have the right to be kids, and kids are kinda loud sometimes, even if you're trying to teach them to be mindful of their volume), but I think that it's generally good to try and show some empathy, or at least ask questions in good faith if you don't understand well enough to empathize.
I'd implore you to communicate with a bit more intent. Calling someone a psychopath is a pretty serious thing to do! Did you intend to hurt someone's feelings that much? Or were you just confused and a bit angry, and came to that conclusion in haste? There's a person on the other side of this conversation who has feelings, and they're asking here for help. They're trying to improve themselves, and I don't think you'd want to say that type of thing to someone who's just trying to live a better life.