"I had no idea YC teams were this competitive with each other."
As far as I've seen, they are not (and, neither of these teams is a YC team...they are YC applicants, along with 400+ other teams). The teams tend to be very well-equipped coming into the game and don't really feel the need to break up other teams before they've had a run at it. When a couple of companies fizzled out after the program, I suspect there was a bit of competition for who would get some of the folks from those no longer existent companies, but I'm sure it was friendly (at least I can't imagine any way it could have been otherwise...everybody is still friendly at the events). Others started working on new ideas of their own rather than joining an existing YC company.
As far as I've seen, they are not (and, neither of these teams is a YC team...they are YC applicants, along with 400+ other teams). The teams tend to be very well-equipped coming into the game and don't really feel the need to break up other teams before they've had a run at it. When a couple of companies fizzled out after the program, I suspect there was a bit of competition for who would get some of the folks from those no longer existent companies, but I'm sure it was friendly (at least I can't imagine any way it could have been otherwise...everybody is still friendly at the events). Others started working on new ideas of their own rather than joining an existing YC company.