Excerpt from the article:

Schenker says that after his years in the service industry, he has watched tipping evolve into a major part of his pay.

“If there is some means of tipping that’s available to you, that should signal to you that workers there aren’t being paid enough,” says Schenker. “Tipping is sort of an acknowledgment of that fact.”

To Schenker, customers who don’t tip are not understanding that businesses treat tips as a baked-in part of workers’ wages.

“They subsidize lower prices by paying employees less,” he says. “If you aren’t tipping, you are taking advantage of that labor.”

He was so close… Especially for someone who says himself does not make much money.