I don't think anyone is claiming that the common case is the developer who stands up for themselves, has healthy boundaries, and doesn't let internet-hate scare them. Most developers fall into this trap, including a past version of myself.
But I think it's a pretty objective fact that this isn't a good way to be. I'd be hard-pressed to find someone that would say that it's awesome to be a doormat who allows others to walk all over them. But with work (possibly with the help of someone like a therapist or professional coach), people can change their attitude in order to have a healthier relationship with their OSS projects, and can develop the assertiveness necessary to enforce their boundaries. If you (not you "you", just the general "you") don't want to put in that work, that's ok I guess, but then maybe you should just accept that you're always going to have a toxic relationship with your OSS projects and with some of your users.
Just to be clear, from your statement:
> But this presumption of "I feel comfortable with X and therefore nobody else needs help with this"
I'm having trouble finding where anyone said this (and if that's what you're reading, maybe you should step back and think about why that is). I see people saying that they're able to set healthy boundaries, presumably as inspiration to others. "If I can do it, don't despair: this is something you can learn too, and it will improve your life." We need not accept that the status quo is the only option, especially when it's a fairly bad option.
I don't know if Tea will be good or useful or will solve any problems, but I do note that it (at least in part) seems like a technological solution to a social problem, and those tend to not work out so well. Or they do work, but serve as a crutch to allow people to avoid confronting uncomfortable truths about themselves.