There's a lot of hate flowing through dA and a lot of it does tend to get directed at the less mainstream types of fetish art. It doesn't help that furries already have a bad rep.
As for e621, that place is way more furry based, to the point where they shit on anything that isn't strictly standard porn or yiff.
I wouldn't take any of the comments personally, but rather use them as motivation to push yourself further and to improve on your fundamentals. TF isn't for everyone. Many people are repulsed by it or think of it as some sort of body horror thing. If they already think that, then they will always think it is unpleasant/undesirable regardless of how well it is depicted.
In such a niche field, constructive feedback is difficult to come by, and positive reactions tend only to be reserved for those at the top of their craft. Even then, they still have their haters spreading negativity amongst other people's praise.
Gryf's raptor tail animation is a good example of people saying wtf, nightmare fuel etc