Yes I'm implying that good waiters currently make more than bad ones "in theory". In that good servers will provide good service, and thus sway the people to tip higher, and then said tip will go specifically to that good server.
I'm unaware of any laws enforcing a tax on anyone, unless the restaurant (or menu) specifies something along the lines of (15% tip mandatory) or perhaps at say a Japanese Steakhouse it's common to see (25% gratuity mandatory for parties of 8 or greater). My understanding however is culturally, in the states, it's considered appropriate to tip 20% to your servers.
But yeah when stating an opinion it's important to say what your culture and country is like. Where I'm from (South East United States), is what I'm referring to. The incident occurred I assume in East US.
On a side note: I find it incredibly inappropriate that a server actually took a picture and turned in to the press simply to paint a bad image of this athlete.