there was a Starbucks downtown in Austin where the store posted a sign asking patrons to buy something to use the bathroom.

The reason for that was due to the store being near a hangout for homeless people.

But there has been a trend by coffee shops to crack down on people sitting in the coffeeshop and sponging their wi-fi. Usually those people are habitually in the coffee shop and only buying a single coffee and using wi-fi all day.

https://www.washingtonpost.com/lifestyle/style/you-ordered-that-latte-two-hours-ago-think-about-leaving-the-coffee-shop/2015/07/08/caa597bc-19ef-11e5-bd7f-4611a60dd8e5_story.html

It sounds in your case that they might have profiled you because of your appearance.

As far as personal experience, a buyer of my sister's (roommate) condo profiled me. Took a photo and everything. She later came back to the condo and apologized tho. Very honorable of her to do so. But being profiled is horrible. No reason for that.