And if you don't tip, or tip lowly you get dirty looks from people that came with you. So essentially you are forced to tip a "regular" amount, or even above. Which completely eliminates the feedback/rating part.

Well, wait, you aren't required to tip above. You're right in that etiquette requires tipping a 'normal' amount (15%) but there's always the potential that you tip above and beyond. Servers are compelled to prove to you that above and beyond tip.

I don't see why it should be limited to restaurant servers, when they aren't the only people serving you.

Hey, I agree with you there. At sushi places, the sushi chefs have their own tipping jars I always make sure to frequent.

All it does is drive up costs for the customers and makes the worker stressed out about being paid a "normal" amount.

Eh, I'd rather work at a place where I get tipped because I know I can make bomb tips because I can work it. I don't want to share my tips, I don't want to make the same amount no matter how good I am to my customers. I will dominate them with my service skills.