I don't think that's true at all. I think there are plenty of people on here who make an effort to understand the issues and then might come to different conclusions about it. And then there are another group who deliberately don't try to understand the issue at all, and take pride in their unwillingness to attempt to understand another perspective.
Most of the prejudice against trans women throughout history (and the present) has precisely been because they've been seen as men who are superficially acting as women. It's slowly becoming more widely understood that that's not what's really going on. But yes, there are legitimate discussions to be had around women-only spaces, where the justification is based on female physiology that trans women don't necessarily share. My attitude with trans women is, yes, they probably haven't had to deal with some of the shit that women have to growing up, but they've probably had to deal with more than enough shit of their own by being trans. And it's not as if trans women have chosen to be trans because they think being a woman looks cool or will get them more followers on Instagram.
People who are accused of blackfishing aren't trying to be part of the black community, they are superficially taking aspects of it. And they are almost certainly profiting from it if they're being criticised. The only question is whether anything is wrong with that. People who are genuinely engaged and involved in a particular community (e.g. Eminem) rarely get criticised in the same way, even if wider society is criticised when the black originators fail to have the same success as the white adopters.