The customers should not have involved her. They crossed the line and she should have been able to refuse to serve them without choosing between that and losing her job.

1. Service staff trade out tables all the time, for any number of reasons.
2. She was fired.
3. You've conveniently ignored the offending conduct.

I have some advice for this waitress and others like her.
You are now in the real world.

In your lifetime you will hear many things that you don’t like. Not everyone gives a damn about PC.
If your job involves interacting with the public you’re gonna have to suck it up buttercup.

Some customers will be boorish douchebags. Some will be rude and condescending.
You do not have to engage them in chit chat or agree with anything they say.

Your job is to put on a happy face and ask them if they are ready to order food or drink.
While you are on the clock you are not the PC police. The workplace is not your personal "safespace".

If this puts your knickers in a twist, after work go home and kick the cat, chug a couple fingers of Jack, do whatever floats your boat and relieves your angst.

The article says the customer was being harrassed.

@LovinLarge The author of the article mentioned harassing, the waitress and owner weren't quoted that way. If they were bothering other customers I would have admonished them or threw them out.

@barjoe The waitress indicated that she overheard the transphobic remarks prior to arriving at the table, so the remarks were being made loudly enough for people other than those at the table to hear. This may be what the author considered harrassment or perhaps there was more. Don't service staff commonly switch out tables for one reason or another?

@LovinLarge I wasn't there.

The issue here is hypocrisy.

Religious conservatives want to be able to refuse service to LGBTQ because they're offended by their orientation, but this server is not allowed the privilege of refusing service to bigots because she is offended by bigotry (which, unlike being LGBTQ, actually IS a choice; nobody is born a bigot). Essentially, the owner was saying "bigots are a protected class and you are obligated to serve them."

Tell them Philly style Joe! LOL!!!

Really the only solution. Unfortunately bigots have a right to exist, but they don’t have a right to cause trouble. Of course, if they choose to express their hate and biases, they should keep in mind, the waitperson is handling their food....

Perhaps, but they made an effort to drag the waitress into it. Had it remained a "private conversation", it would have been something entirely different.
I hope she wins her complaining.

This is about harrassment of the other customer and the waitress, not about opinion.

@KKGator Yes the customers crossed the line when they involved the waitress. They also crossed a line if the person they were deriding could hear what they were saying.