First of all, this guy is only 37, so it's not like he's 60. And I have no problem with Starbucks exercising its rights to refuse service to anyone. However, the situation was handled badly. A manager should have taken the man aside and explained the situation before getting the police involved.
The 37-year-old man passed a note to the 16-year-old barista asking her out on a date. It is understandable that the teenager would feel uncomfortable with him frequenting the establishment. He clearly knew she was much younger than him and should not be subjected to advances from customers just because she was polite and friendly.
A teenager should have a right to live in peace. She should be able to go to Starbucks if she wants to. She should have the right to order her coffee without an older man being there to make her uncomfortable. Starbucks has a right to protect itself from lawsuits if the girl were to ever want to sue.
Ageism is not to blame for that incidence. Starbucks had all the rights to ban the all man from their outlets because of his unbecoming behavior. The moral fiber of our society has weakened and things that were considered a taboo have now been embraced, no wonder people are finding things weird. Old men should keep off young children.