Find another job if you don't like it, or...
give good enough service to deserve a gratuity.(something given without claim or demand.)
I've been saying the whole time that a good server will do their best, especially since their tip will likely correspond with their level of service. If they do their job as expected, it is proper and assumed that you will tip accordingly.
Years ago, tipping was considered to be on top of regular compensation.
Eventually, it got to where restaurants didn't pay their servers anything, and they still wouldn't, except the government makes them so they have something to take taxes out of.
This whole conversation is very odd. It's odd that Christians, upon whom grace has been lavished, cling to an attitude of justice instead here.
And commissioned sales are very different. You automatically get that commission when you make a sale. Tip-based wages are not guaranteed, since it's up to the customer to conform to the standard.
Do whatever you want, just keep in mind that most servers want to do a good job. They aren't out to get you because you're a Christian or for any other reason.