Let me break it down somewhat.

I (the customer) order a service (pizza) from a business (pizza hut)

I pay the business for this service

I do NOT pay the person who makes the pizza (the business pays them)

I do NOT pay the person who takes my order (the business pays them)

I do NOT pay the person who makes the boxes the pizza is delivered in (their employer pays them)

I do NOT pay the person who delivers the pizza (their employer pays them)

It is not my obligation to pay employees for services that I have paid their employer for.

if the delivery guy has to go through a snowstorm, alien invasion or neo-nazi rally, I will probably tip them because that's service ABOVE what I expect.

I am a server. I have no idea what your personal beliefs are, nor do I care, but I am going to do my best to serve you and give you a pleasurable dining experience, as much as I am able.

yes, because that's your job and you are paid by your employer to do it.

The expectation is that, in return, you will tip me.

No, because in return of doing your job your employer will pay you.

When you don't, regardless of the meta ethics and political issues at hand with regards to the culture of tipping, the fact that I am paid below minimum wage, and the fact that minimum wage isn't really a realistic metric of how much someone needs to survive in today's world, despite all of this, if you don't tip me, I lose money, TODAY.

THEN TAKE THAT UP WITH YOUR EMPLOYER FOR NOT PAYING YOU A LIVING WAGE

HOLY SHIT