It was a poster here that used the term "political enemies" regarding this situation, not Trump as far as I know.
In this situation with the Warriors the term is of course not accurate, as Steph, the coach, and the handful of players who'd expressed doubts about attending the WH invite are not political actors but entertainers. However, when they express political opinions to millions of people who's adoration they've earned, they are acting in a manner that affects, either by reinforcing or challenging, their fans' political opinions on the current administration.
Therefore, it's my opinion that if Trump used the term now, or if Obama had used the term during the Tim Thomas situation, Jacob Volkmann situation, or certainly the Tom Lehman situation, I'd have a hard time disqualifying the validity of the term "political enemy". Mostly I'd want to see enemy replaced with opponent, but I'm just rolling with the term a poster here used to characterize Trump's response.