They're a 501(c)(6) trade association if you want to be technically correct. Which is different from 501(c)(3)'s which are what you normally think of as "non-profits" but it's still an exempt organization like a chamber of commerce.
Fun fact: The NFL was a 501(c)(6) organization at one point because "professional football leagues" were specifically named in the IRS code but they voluntarily dropped their status.
Fun fact: The NFL was a 501(c)(6) organization at one point because "professional football leagues" were specifically named in the IRS code but they voluntarily dropped their status.