If you've dealt with the American medical system then stories like this aren't very surprising. I'm not going to act like this is everyone's story (a lot of people have pretty smooth experiences) but it happens a lot more often than it should.
But GP's point is otherwise true. It's just a job to them. They see dozens of sick people every day. There's no way to be empathetically engaged with all of them or really any of them and still be effective. It's not personal, and they aren't ignoring you. You're a bug report in their ticket system. Understand that and you'll be able to deal with the system more effectively.
The exception to this rule is if you are in an HMO like Kaiser which force you through "level one support" (your GP) or if the specialist is so busy they require a referral to screen out the social media schizos.
If you saw a concierge specialist that is cash pay only they'd probably see you no matter what though.