Starbucks founder and chairman Howard Schultz has been critical of Donald Trump. Credit: Jason Redmond/AFP.

CREDIT: Getty Images

Recently, Kayla Hart walked into a Starbucks in Charlotte, North Carolina and ordered iced green tea. Instead of writing her name on the cup, the barista wrote “Build a wall,” so that when the beverage was ready, store staff shouted out “Build a wall!”–laughing loudly. Everyone in the shop turned around to see what was going on, and Hart walked out because she was too embarrassed to stay. The reason for all this is that Hart was wearing a Donald Trump t-shirt.

Hart complained to Starbucks, and also to the local media, and the story has received widespread attention. Starbucks issued this statement to a local news channel that covered the incident: “We failed to meet this customer’s expectations of us, and we have apologized and are working directly with her to make it right. This experience is not consistent with our standards or the welcoming and respectful experience we aim to provide every customer who visit our stores. We have spoken with our store partners about this situation and are using this as a coaching opportunity for the future.”

That’s fine as far as it goes, but it doesn’t go far enough. I’m not a big fan of people losing their jobs. I’m also not necessarily a fan of Donald Trump. But in this instance, there are compelling reasons why the company should fire or at least meaningfully discipline the barista in question, or maybe several of them. See if you agree:

1. Your politics shouldn’t kill your professionalism.

Howard Schultz, Starbucks chairman, and until recently its CEO, is no fan of President Trump. He’s been caught on video saying that Trump is destroying the economy, and the company famously responded to Trump’s anti-immigration actions by hiring thousands of immigrants. The company has also been the target of boycotts from the right, most recently for the odd reason that its holiday-branded items were non-denominational (rather than overtly Christian).

So far, Starbucks has provided a great case study for how to take a political position without losing customers over it. The boycotts don’t seem to have done the company much harm. And indeed, given where most stores are, its Seattle roots, and the demographics of who’s more likely to pay for a Starbucks latte versus a McDonald’s coffee, having an anti-Trump slant probably isn’t bad for business.

But having a political viewpoint doesn’t mean it’s OK for employees to jettison customer service standards and even basic courtesy when someone they disagree with walks in. Starbucks needs to do more than just issue an apology or “make it right” with an individual customer. It needs to make that point in a way both customers and employees will take seriously.

2. Starbucks needs to show fairness.

This didn’t. If I walked into a store in a chain known for right-leaning sympathies–say, Hobby Lobby–wearing a Barack Obama t-shirt, I might not expect a hug, but I would expect to be treated with the same courtesy as any other customer. If that didn’t happen I’d have just cause for complaint and restitution.

In our increasingly polarized society, it’s way too easy to feel that every place you go is either a friendly location or enemy turf. That’s not a good thing. At the very least, when people from an enemy camp enter our territory, we should treat them as we’d expect to be treated if we entered theirs.

3. Starbucks should welcome everyone.

Some observers have noted that people feel particularly defensive around their daily caffeinated beverages. That may be true. But more importantly, Starbucks is a company that operates nearly everywhere and wants to cater to everyone (or at least everyone who can afford to drink lattes on a regular basis). Nearly half the voters in this country voted for Trump in the last election. Does Starbucks really want to send all those customers away?

4. Starbucks has done a good job of staying away from personal attacks until now.

One strategy that has won the coffee chain a lot of praise is the way it’s challenged Trump’s policies and decisions but not lashed out at the president himself–even though Trump made an empty threat about not renewing the Starbucks lease at his property or properties during the Christmas boycott.

The Charlotte baristas stepped way over the line that separates political disagreement from personal insult, though. If you’re going to be a company with open political opinions, then keeping to the right side of that line between disagreement and insult is really important. Disciplining the baristas would demonstrate that Starbucks knows and cares where the line is.

5. It’s never OK to be hostile to a customer.

Today’s political climate is so acrimonious that it’s easy to forget the norms of civilized behavior. So consider the scenario for a moment without that element. A woman walks into a store and merely because of her appearance, the staff mocks and humiliates her until she flees. Take politics out of the equation, and it becomes very clear that this should be a firing offense.

6. A lot of people are watching.

This has turned into a high-profile event. That’s why Starbucks must deal with it in a public way, by firing or disciplining the employee or employees who are to blame. That’s bad luck for them. If they’re at the typical barista age, it may provide a lesson that will stand them in good stead through the rest of their careers.

7. This was not an isolated incident.

This is the biggest reason why the baristas can’t be allowed to get away with it. Because Schultz and Starbucks have taken definite political stands, they’ve become targets of Republicans and right-wing groups. There have been several incidents of antagonism at stores, including an effort by Trump supporters to have everyone give their name as “Trump” when placing an order, and an argument in which a customer claimed he was denied service for being a Trump supporter.

In that last case, a witness reported that the man was just annoyed because his coffee was taking too long and the barista denies that the delay had anything to do with his politics. And that’s the point–because Starbucks’ political views are in the spotlight, it’s even more important than usual for the chain to make sure that its employees behave with professionalism. These baristas didn’t, not even close.

The opinions expressed here by Inc.com columnists are their own, not those of Inc.com.