I take no issue to mean comments if it's point is to criticize bad writing in a chapter or plot. If anything I have bigger problems with comments that are ruthlessly positive no matter what the author does. Take Tower of God, for example. The comments under it over at Webtoons are disgustingly positive all the time with the top comments shrieking the same three things; "Like the chapter ya'll! Let's get TOG back where it deserves!" or "I bought fast pass and it was definitely worth it and you should too!!" or "Don't forget to like the chapter ya'll! (long rant about how great and hardworking the author is)".
This bothers me because while TOG was a great webtoon and the art is only getting better it's gone down in quality in every way that matters to me, and none of their fans on Webtoons are addressing this. I say Webtoons because a lot of their fans over at the TOG subreddit actually have.
In short, baseless criticism is damaging to a growing work of art, but baseless positivity is perhaps more damaging to a declining work of art. That's why I encourage "rude" comments, so long as they're constructive and have a valid point.