What I've seen (not very often fortunately) is people who seem to have the idea that there is One True Way to be trans.
There's one trans woman I know in real life who, when I described myself as "possibly M2F", said something like, "no dear. It's WBT -- woman born trans. We were always women" in a tone that did not invite disagreement. I have a great deal of respect for her otherwise, but this convinced me that she is not the person who I would discuss my transgender feelings and confusions with.
On this site, I've occasionally seen a poster be rather arrogant towards people who they thought were not dealing with their situation in the right way, including calling them mentally ill and saying they should check into a hospital. I don't know what the mods did about it, the person is still posting. One such case was IMHO the trigger for the stoush which resulted in most of the active NBs leaving susans.org. So, yeah,
susans.org is not immune from this.
I don't know a lot of NB people (well, I don't know all that many trans people, period), but I did meet a lot at the Phila. Trans-Health Conf. They were mostly younger (in their teens or 20's), and from what I could see got along less because of identifying as the same thing as because they cared about one another and were willing to accept and respect and even defend one another's peculiarities. (E.g., correct me when I misgendered one of their number, which I did rather often, I'm sorry to say.)
I think the key is respect, especially respecting that behaviors, identies, and sensitivities that you don't understand. Just as we trans people would like cis people to respect our understanding of our own gender, our name and pronoun preferences, and our choices as to how to deal with the conflict between our own needs and identities and the outside world (e.g., transition or not), whether or not they understand them.