There is nothing more miserable than working with a team that cannot and/or is unwilling to work with anything but their language of choice. But honestly this typical goes even deeper than language. Its often difficult to get a team to work with something outside of the framework they are used to. Even if it could take 3 times as long or even is just flat out impossible without it.

In my experience it has everything to do with developers who like to feel under control and feel really uncomfortable if they are not the smartest person in the room.