Python made the unfortunate but understandable decision to split the community. It's really hard to make a non-backwards compatible change in an open source community because you can't make anybody move.

My $0.02 is that Python 3 is clearly better, and that if you'd use python for something new it should be 3. But I also think it's unfortunate that the community is in the sort of state where people ask this as a legitimate question in 2017.

Progress requires python 2 die, but it's taking its sweet time.