Why not block and move on. I really empathize with what you're saying but I feel it's unproductive to seek out debates or to spend time in toxic fandoms where people are bigoted or ignorant. I would rather focus on offline activism and keep online fun. Sometimes that means a lonelier fandom experience, since I share it only with closer fandom friends, and sometimes it means leaving a fandom, but it's better for me than wasting my time on being upset while trying to enjoy my hobbies.