I didn't say it was a deal-breaker, but it is a red flag to me. These guys all live and breathe basketball. They are basically "putting in an application" to play for one of only 30 teams in the league. This is their lifelong goal, and they all say that they watch NBA players all the time to see who to model their game after.
You can't be prepared enough for an interview to at least know the names of the top couple of NBA players on each team, when basketball is your "life"? At least maybe know that Fox and Sabonis are the two top players on the team? I don't expect anyone to know every player, but maybe the top 2-3 at a bare minimum?
It strikes me as being lax in preparation and situational awareness. You should be cognizant enough to know that all of these interviews will be scrutinized and do some minimal, basic preparation for these things.