If you host a tournament for any sort of competitive game, it was always going to attract competitive players who want to win prestige and prizes, even if those prizes are only worth, at most, a few hundred dollars. It would be the same for any game with a competitive scene.
If Phase wants to have actual community members compete in the future, rather than pros, I think entrants should have a YouTube or Twitch account membered to one of the talents before July 20, or has a receipt for a superchat or the Phase store before July 20 would work (the contest was announced on July 21).