I’m honestly always a bit unsure about this topic. From one side I don’t want to generalise and being ableist because:

If your critique is that he’s dumb because he has a stutter

This is objectively wrong and I totally get it. On the other end, we don’t live in a perfect world and to convey some emotion we need to use words that have a baggage or are imperfect. In any case, my personal meter for judging is always the intention and the context, more than the word itself.

Do I think every person who shutters is dumb that’s why I used it on Biden? Of course not.

Do I find hilarious thinking at Biden in a pool of shit having an heart attack and trying to spell “help”? Absolutely yes.

I would have liked the meme more if on the Trump part there was “shits himself”.

It’s the contrast the point, putting a man of power who should project this idea of “alfa” man with the reality of normal human disability. It puts them at our level, where we can bully them.

You are right if he was a person, but I don’t pity insects. I hope he gets an heart attack while shitting and dies stuttering asking for help.