You can't deny that there are some extremely divisive personalities in the aikido world. This is part of the problem, and my personal feeling is that this is very difficult to get around. On top of that, there are some excellent teachers who are very poor managers of people.
On the other hand, some of the old-timers are (or were) people with high personal integrity, and seem to have had the rare gift of being able to build bridges. I understand that the late Kisaburo Osawa was a prime example of the latter.
I have personally had my own share of top class instructors who either had divisive personalities or were useless at man management.Some others imo got bigheaded and lacked respect for their sempai.It seems to me that a lot of people want to be BIG CHIEFS.This is why I mentioned in an earlier comment I admired Murashige /Jack Arnold Sensei.Until we as teachers realise we are not masters, but servants to our respective students and we owe a debt of gratitude to everyone we have met during our own journey we will just repeat the same errors over again.
In the U.K for example, from 1966-till today , you see little evidence of fraternal , welcoming , open door policies existing between groups.Cheers, Joe.