At the other extreme, if you want to join your local flying club, you can expect to be treated courteously. If anyone treats you like an asshole, the problem is with them rather than you. It can be that way, because the group is not trying to achieve anything extreme, its just for enjoyment and largely social.

If you want to join in the white hot stream of activity surrounding one of the world's most important pieces of software, its not going to be like your flying club.

Its not quite the marines either, but it is a place where very complex stuff has to get done, urgently, absolutely correctly, in the face of hundreds or thousands of interjections and "what about" from more or less well-meaning contributors who just don't have or get the big picture in the same way the core of the group does. (Talking about Linus here, not Trump :)

Sometimes, such an environment functions better with a culture of abruptness and "take no shit" is built.

Its very unfortunate for anyone who aspires to join such a group that they have to put up with that. But sometimes we have to acknowledge that that "terrible behaviour" is part of what makes the group work. Not all clubs are suitable for all people.