The main reason for the problems related to inclusion, and supportive environments are due to people seeking answers from community builders rather than from the disenfranchised. Myths and presumptions about people who don't fit in are too convenient and are rarely challenged.
I can tell you from what I've witnessed and experienced that this problem is epidemic and leads to some of the worst of what is consistently dismissed as "societal ills." I don't know more about this than anyone else does, but I know more about it than I do about anything else.
People are so concerned with being part of a group or designing one that appeals to them that they never concern themselves with how exclusive they are or how badly people are hurt by it. It all just blamed on peoples unwillingness to conform. Diversity is too often a commercial brand that does little more than encourage identity politics and the very attacks (the bullying) which is claimed to be what people are attempting to prevent.