I'm definitely not involved with any of them to know for sure, but my guess would be that's because non-profits come with a lot more regulatory overhead in comparison to for-profits of a similar scale. Not saying that's bad in any way, but for a team that just wants to build the damn thing, for-profits are absolutely less of a hassle.
Sure but if they want people to donate they better be ready to explain their decisions. All that extra overhead is there to ensure that the nonprofit is actually a nonprofit doing what it says it's doing after all.