OK:
-Being a beginner artist.
-Being a kid.
-Having an opinion about art.
-telling people exactly what they are doing wrong and tell them how to do the right thing.

Not Ok:
-Being a bad artist and refusing to even try to improve.
-using “It’s my artstyle” as an excuse to use bad anatomy on everything you draw.
-Insulting other’s people artwork instead of telling them what they are doing wrong and helping them to improve.
-Stealing/tracing art and claiming it as your own and block everyone who calls you out of your shit.
-being an asshole.

I'm on the fence with this one. On the one hand, OP is right, a lot of beginner stuff tends to look pretty bad. They're stepping stones and they need critique, not discouragement.

On the other hand, there is a crap ton of really BAD art out there. Just… horrible stuff.