How is that different from what you described you doing? Are you not going there, and working for a couple hours, and probably not constantly purchasing large amounts of food or drink?
You seem to have a righteous indignation about people doing what you've described yourself as doing.
I think one drink per 2 hours is pretty reasonable. Maybe it should be one every 1 hour, or maybe one every 4 hours is reasonable. At the end of the day, it's convenient and helps make the coffee shop owners money, but it's not a coworking space, and I'm a fan of "fair share".
You seem to have a righteous indignation about people doing what you've described yourself as doing.