To me, an author who gets into an argument with a reader of theirs in the comment section because of something the commenter said....is a major red flag.
Even worse, are the ones who make those passive-aggressive posts in forums where they don't say the name of the reader whose comment upset them, but they heavily hint at it enough to the point that anyone who witnessed the discussion/argument, knows exactly who and what is being referenced. I avoid those authors like the plague. They aren't mature enough to be engaged with.
If you can't handle criticism, even the kind you THINK is trolling, even if writing is just a hobby for you....than you shouldn't be posting your work publicly.
To me, its like when people wear something that is obviously "eye-catching" in public, and then someone else makes a remark in public that you are offended by. You don't get to police what people can and can't say. You CHOSE to do something that grabs attention, so you have to accept the consequences of garnering said attention whether you like it or not. You don't get to have it both ways. You aren't special.
Same for writers, you chose to post something in a public space, so you WILL get both the good and bad of this exercise. Suck it up, or stop posting/engaging.