Maybe there's some rare incident, maybe they're just annoyed the teens don't spend enough per hour. It doesn't really matter. Teens aren't some special danger, and it's bad when places want to give off the impression of being a nice public place but fail to be one in significant ways.
It doesn’t matter to a non stakeholder like you. For the business owners, it clearly matters.
What they think has very little relevance to the problem of teens having nowhere to go.
And in general the US has been really lacking in third places.
The late 80's and early 90's was peak mayhem but kids still hung out unsupervised at the mall.
Sure. But the end result is still teenagers losing a place to go.