It is completely within his duties to do that. It is also completely within Delta's duties as his employer to question his judgement and fire him for being a racist later.
Seems like the only reasonable response.
As for why pilots have the power to boot people, it's because they're responsible for the safety and happiness of the passengers during the flight, and the airline is there to make money on slim margins, not to serve as a public utility. Unless an airline engages in systematic discrimination against a protected class of people, then pilots will generally be allowed to appease the majority of paying passengers.
Free Speech (but only when we say so)
There are places for expression and "Free Speech"... maybe sitting next to the 13 year old or grandmother (or any other paying customer) who's flying for the first time in his/her life wearing some silly t-shirt about bombs and anti-government banter isn't the right place for it.
Does this then imply I don't have a right to live, because "rights cannot be denied based on the ability to pay"? That I don't have a right to property, because if I don't pay my debts my belongings can be confiscated and sold at auction?
I have a right to appoint my own counsel, but the government won't pay for the counsel I appoint. In order to use that right I have to be able to afford the lawyer I want.
US citizens have a right to run for elected office, but clearly that's not provided free of charge!
Rights are not irrespective or independent of my ability to pay. And if something is a right does not mean I get it for free.
I think you need to lay out your argument in greater detail than you have done so far.
To say that carriers should be able to selectively revoke this abstraction and deny travel to specific individuals is to give them the power to force arbitrary rules on anyone who relies on this infrastructure. This would make all rights subject to the whims of the airlines.
The idea is that Congress cannot criminalize speech. But the ramifications of your free expression, with respect to those people and institutions that you interact with, is not regulated by congress in so far as a crime is not committed in reaction.
Could McDonald's legally deny me entry to their restaurant if I was wearing a T-Shirt that said "I support Obama"?
Further, can they legally deny me entry for no reason at all?
(I'm not trolling, I genuinely don't know the answers)
Edit: I guess specifically if being in that protected group played into why you were denied. Meaning, they can toss you for being drunk even if you're in a wheelchair.
It's not a republic or democracy when you're on his plane. What he says, goes.
In this case, the plane had not pushed back from the gate. The pilot kicked this guy off before the flight. I think it's reasonable to ask why a random, unjustified passenger complaint to the pilot should override the TSA's screening process.
This way leads to fundamentalism.