Thriving in a competitive lab
From what you are telling, your advisor has not bred a competitive lab but rather a horde of children. The behavior you are describing is unacceptable and shows no respect for each other at all. It normally is the professors job to make clear how the lab is working, to make sure the speaker in a talk is listened to and discussions are postponed to a break or after the talk, etc.

Furthermore, if everyone in the group is competing over a task, this shows that they don't have enough tasks of their own and go for everything that is available. Once again, it is the professors job to have regular discussions (in private!) with lab members about their current projects, to make sure that they go along well and that such a case as you described in the last point, i.e. everyone has nothing to do, does not happen.

All in all, it looks like this lab you are describing has no real leader, no one capable or willing to set ground rules and advice and guide everyone. I think and hope this is not the common case in labs and would advice you to avoid such a place if possible; maybe you are able to find a new advisor?

Side note: Of course competition will always be a thing and a healthy competition is good. But what you described is not healthy at all and in all the labs and research groups I visited so far (math, CS and engineering mostly), there was a decent amount of respect for each other.