My point is that if someone leaves a 20% tip, that goes to the server and whoever they need to tip out like bartender and busboys. But it goes directly to them. When a business implements a service fee, that direct line to the service worker goes away. If I'm told there is a 20% fee to pay staff, I expect it to go directly to staff.

I'm all for dropping tips and paying living wages. But a "service fee" isn't the way to do it. Just raise the damn prices.

A mandatory 20% fee is just the business saying that everyone has to tip 20%, and trust us that it actually goes to the servers/staff. There is functionally no difference culture-wise between giving consumers the choice to tip 20% and mandating a 20% service fee. It's the same as the "gratuity added to parties over 8."