Their employer is treating them like a tipped employee, which is so embedded into society’s fabric that we have a separate tax code for it.
You not liking that is not any different from you liking a given law. You’re free to not participate, but expect there to be consequences, and one of those is for people to assume you’re intentionally being an asshole, not protesting a perceived injustice.
Unironically the answer is “shop less.”
Prices on goods rise when demand for goods stays sufficient to support the price going up. The less everyone buys, the less things will cost.
Prices for goods have almost nothing to do with the price of rent, but the mechanisms there are the same - it’s just that you have to encourage building rather than “live somewhere less” because the second option really isn’t tenable, for obvious reasons.
If you want rent to come down, campaign for, vote for, or even run for office to be the candidate that will change zoning laws and encourage building multifamily housing.