The presence of those people on reddit never bothered me much. They stayed in their own niches and I stayed in mine. I’m fine with the idea of individual communities being safe spaces for particular groups but it’s likely impossible for any place to be safe for everyone.
A general purpose cooking community will be unsafe for vegans. A vegan community will be unsafe for BBQ chefs. A programming community that I want to be in might be unsafe for Java programmers (never date a Java programmer–they will treat you like an object). The best you can do is make sure that participation is voluntary and that edgier topics don’t overspill too much.
I’ve been on Usenet for decades. It was and is completely unmoderated. It was eventually destroyed by spam, not by bigots.