I think since the community is fundamentally built around a sexual preference/kink/fetish, it is not that surprising that most of the people use feedism subreddits and sites primarily for porn. So most people in these spaces will be looking for sexual fulfilment rather than romantic or platonic ones. This is probably why most people you talk to are disrespectful, apathetic and don't care about you as a person.

I am not saying this is justified, and ideally feedist spaces would be more wholesome and about body positivity but in reality it's more like looking for someone to care about you as an individual in the comments of xvideos.

Thus, if the basis for interaction is 99% sexually motivated, that leads to shit like this yea and it's unhealthy.

While social acceptability is ofcourse a huge thing, I don't think that's the particular problem here. People might also just disregard you because there looking for pics or certain kinds of interaction and if you don't give that to them, they move on, since there is plenty of supply and demand. I might have understood this aspect of your post though. I hope this is relevant to you.