Edited - Bose is correct. Ultimately the responsibility lies with P1. However, if P1 doesn't know any better because that is the environment he has grown up in, then there is still a need for some soul searching.
Indeed and I would bet that anyone who survived and applied peer pressure consciously or otherwise should indeed be soul searching.
But there is a big difference between soul searching and a full blown witch hunt.
As I said unless the pilot was forced to make the flight under duress then the responsibility for legality and planning lay with him. As did the ability to divert. There is no evidence that he was forced not to divert by the other pilot when they knew the conditions were deteriorating so again poor judgement.
This just boils down to poor judgement, pure and simple.
As for the comments of the controller unfortunate, but I suspect that they have beaten themselves up about an ill timed comment. But once again how does a controllers inappropriate comment change the fact that the flight was illegal and badly planned?