It’s a gray area.
Yes, in an “employment at will” state the employer can fire you at will and doesn’t have to go through the elaborate process I described. It just puts the employer at risk. As to whether or not the employer would lose in court… that would depend. If, for instance, someone claimed to have been fired because they were, say, Jewish but 2/3’s of the company employees are Jewish it’s not likely the court will side with the fired employee on that one.
One of the risks of setting up an elaborate system, such as my company has, is that if they don’t follow the policy and procedures and it winds up in court it will work against them.
Although there have been some highly publicized cases where employees win against former employers, in most instances the company wins.
Your example of someone being fired because they’re gay, then taking it to court, isn’t so great - homosexuals have little protection under the law and it is still legal in many areas to fire them simply because they are homosexual.
The size of the company has something to do with this. A small employer with 2 or 3 employees is much more likely to yell “You’re fired!” and boot someone out the door – and less likely to get sued. There are two reasons for this. For one, a very small employer is not as constrained by many labor laws. Second, an employer that small just doesn’t have a lot of money to go after. It’s usually less trouble to simply get another job than to take someone like that to court and attempt to get a judgement from them (money being the only thing you get out of that sort of court case). A larger company, however, is perceived as “deep pockets”. People sue the company I work for all the time - and not just the ex-employees. There’s this perception that because we’re big we can somehow “afford” to pay out in lawsuits.
I’ve seen employees fired, turn around and sue, and lose. And I’ve seen employees fired, turn around and sue, and win. In the former, it’s because they were fired for good reason i.e. not doing the job, falling asleep at work on a regular basis, not showing up, vandalism, etc. In the latter case, one I know about from being a witness, a supervisor was blatantly racist. Yeah, think the company dropped the ball on that one, but the supervisor responsible was fired, too. Then the former employee dragged the ex-supervisor into court to sue her again, personally.
And there are a few instances where the labor laws don’t apply equally. For instance, in an operation run by a church it IS legal to consider religion in hiring. The government will not force the Catholic Church to hire a practicing Satanist, for instance. If a business MUST run on a Saturday then they may not hire an orthodox Jew (but they better be up front about that in the job interview, and be able to prove why Saturday operations are so essential and can’t be worked around). There was a dust-up over Sikhs and hardhats in the construction industry awhile back - the Sikhs wanted to wear their turbans instead of the hardhats on job sites, citing religious reasons, and the construction companies said their hands were tired, they’d lose their insurance covereage (which they were mandated by law to have) if they allowed anyone on the sites without specified safety equipment. I forget how that turned out, but it spent considerable time in the court system.
So while the concept of “employment at will” seems pretty simple, in actual practice it’s gotten complicated thanks to lawyers and the animosity between various groups and factions in the country. It’s great that so many different sorts of folks manage to co-exist in this country without killing each other (in contrast to certain other parts of the world) but we do get things like the Sikhs and hardhat conflict which is less likely to arise in a more homogenous society.