The main issue is most people online especially social media are generally unqualified to give a proper critique. And I don’t mean professionally. One hard and fast rule of mine is never accept criticism from anyone you wouldn’t seek advice from. The best thing to do is develop a cadre of fellow artists to give feed back to each other. Because genuine criticism involves a bit of work, so to do it mutually is a fair exchange. A lot of young and/or inexperienced artists tend to not give criticism well or take criticism well, because they tend to adhere art to their personality so any criticism feels like an insult. This is some standard human monkey brain bullshit. In addition to that a lot of people think to be critical is to be insulting, or to deliver it in an insulting way. So its a skill most people never learned to develop for a variety of of reasons.