I have found in my own experience that very often people have trouble taking responsibility for their actions when they are confronted. You confronted them with honesty and truth, and only one had the decency to own up to the behavior and apologize. That says a lot about this group and about the individuals who could not step up and apologize. Be glad you got even one apology.. imagine if NO ONE had replied?

This is just how people are... you cannot expect people to always be so mature, self reflecting or responsive to being called out on their behavior and treatment of you. Also, most people prefer to avoid confrontation, especially over text.

This clearly was the wrong group for you. Good riddance and carry on.