It really isn't worth playing with neckbeards. They don't care enough about the game to let anyone else do their thing (Because it's all about them, after all), and they take it too seriously for anyone to have fun with it.

That...that sounds incredibly creepy.

Things like this are exactly the reason why I waited so long to try out D&D

Starting off I would suggest talking to that specific person in private, you will hopefully not have to say out right that you don't want to DM some hentai weeaboo shit but you could try things like "I'd rather not DM a system that is so different than what im used to" or " the way the system feels is a little too unbelievable for me to be comfortable DMing" and you could suggest DMing something else.

If the above doesn't work, heres me playing devil's advocate:

Make things hard for that guy specifically and in general be a good dm to the rest of the party but try not to make it obvious you are doing it at first but get more and more obvious. For example:
Oh they are disarming a trap? They only rolled average? Trap goes of with specified square it effects is over where that catgirl is. They question it and say its to fight against the locals who have made specific trap disarming tools for use at a distance.

If there are any class features like the favored enemy ranger class feature (small bonus to hit vs specified chosen creature types) then everything has it vs catgirls.

I've been roped into a similar situation and we meet up Wednesday to continue it. The system is essentially the same due to most of them being new and wanting to learn it piece by piece. Anyway, one of the PCs is pretty much the one described and he would not trust anything I did. He used magic to identify all the poisons and lift the curse on all weapon.
It was really irritating but I had to deal with it until the opportunity came up to severely scar that specific character.

No no i didnt mean that at all, i mean the chunky red one that appears above every enemy.
But yeah chunky jam effects are being a bit overused, i love Dead Space for the fact of no HUD, i just find it makes the experience all the more cinematic.

Fair enough. I think it'd be interesting to see how that would work, even if I might not necessarily agree with it entirely.