There's a common trick you can use in those places to get honest critique, use an alt account and completely demolish your own work, say it's traced, say it's uninspired, say the linework sucks, call yourself a tranny, etc.

The karma system on Reddit and the faint presence of the mods on forums creates some sort of bystander effect where everyone wants to talk shit but nobody dares being the first in line because what if they got downvooted, what if this got them banned ? But the moment some other guy jumps in and says more or less what they would have they'll feel justified in posting something like

>first of all, YIKES, my they/thems dudettes, I do not condone what the other guy said, BUT the perspective /anatomy/ whatever could use some work, here's a tutorial...