I'm lucky in that I get very few negative comments. But if I do, it depends on the specifics.

I usually try to put rose-colored glasses on and see if they have a point. If they do, I reply as if their comment had been polite. If it's pure negativity or even trolling, I either hide and ignore their comment or say something along the lines of "Thanks for that and thanks for reading" and don't engage any further.

On rare occasions, I’ll engage a bit more with purely negative comments, but then it's usually for the sake of onlookers, i.e., to put my (hopefully) reasonable point of view out there.