If I were in Colorado, and if I had wanted to vote in a Republican primary, I might be pissed, too. If I really wanted a primary, I would need to get involved in local politics and work toward that goal.
But I’m not in Colorado, and I have no say about how they operate. Nor do I particularly care. It’s their business.
I’d also be seriously annoyed if voters in Colorado (or Florida or New York or Oregon, for that matter) tried to mess with the electoral process in Texas. None of their business.
The Colorado Republican party (not a government entity, but rather a private one which invites other Coloradans to join) made rules last year about how they would select their delegates to the national convention.
The Trump campaign ignored those rules. The Cruz campaign didn’t. Simple as that. Trump lost. Trump pitched a fit, tried to blame Cruz for his own failure.
Doesn’t matter how much Trump whines, he’s the loser here. I doubt anyone will even remember it by August, no matter how many ugly insults Trump tosses as he unwinds.
Trump is running as a reformer — of course he will show the things he doesn’t like in the ugliest possible light. He might have even permitted this to happen for that very purpose.