If the vast majority of someone’s interactions with white guys were being on the receiving end of harassment from stormfront types, I would understand if they assumed I was the same, and I wouldn’t blame them for it. Of course, the vast majority of white men don’t hold or act on those views, so it’s rightly seen as a crazed minority and not a valid basis to discriminate against all white guys.

Your challenge is that you’ve chosen a way of being anonymous that puts you in a relatively small, easily identifiable subset of all the people choosing to be anonymous online. The vast majority of what people see coming from that subset is horrendous. That’s not your fault, and I’m sorry you have to deal with being written off because of the actions of others, but the approach to anonymity that you’ve chosen has been hijacked by assholes, and as I said earlier, with no way of saying who does and doesn’t get to be in your subset, there’s nothing you can do to stop it.

So: you can choose to stick with your current approach, or you can choose a different approach to anonymity that achieves the same outcome, but it is your choice and the consequences of it are on you.