The way to approach these questions is from the rights of the workers.
The people who work at the restaurants have a right to a healthy and safe work environment (this is why smoking was banned in restaurants).
These worker rights trump the "right" of someone to be able to go to a restaurant in a way that puts workers' health at risk. The reasons is because that worker has no choice, while on the other side, the other person has choices of: 1) get vaccinated or 2) feed themselves by making a sandwich at home.
Your example was interesting. There are more laws protecting worker safety than there are laws protecting restaurant patrons.
For the purposes of covid I'm not sure if that is a black and white situation legally, at least in the U.S. Neither the rights of workers or patrons are spelled out as constitutional rights, because the constitution limits the government. This even kind of came up in the Supreme Court, which said that OSHA does not have the right to mandate vaccines in the name of workplace safety.
But doesn't the degree of danger and the trade-off involved in lockdowns matter? There's been a lot of mitigations against covid, some which make more sense than others as we've learned more, some that have costly effects - both financial and otherwise, especially for young people. Some look at the total count of 931k dead in the U.S. and want to do more. Some look at the same number as 1 out of 350 of the population, skewing old and unhealthy, and think we've done too much. We don't close restaurants for the flu, which kills tens of thousands of people.
I don't think this comes down to just a workplace safety issue. I think the degree of danger is quite important, and honest people have very different opinions of the risks and tradeoffs involved. The degree of danger and the mitigations required to make a difference in that danger are better known and quite different than two years ago. That is why there will be more and more calls to remove the existing mitigations.
I've always felt we should have put more effort into supporting those who are feel they are vulnerable, rather than punishing those who are not.
I've felt especially bad for young people who are at minimal risk from covid, having their lives turned upside down, who will inherit the extra trillions of dollars of debt all this will have cost.
The people who work at the restaurants have a right to a healthy and safe work environment (this is why smoking was banned in restaurants).
These worker rights trump the "right" of someone to be able to go to a restaurant in a way that puts workers' health at risk. The reasons is because that worker has no choice, while on the other side, the other person has choices of: 1) get vaccinated or 2) feed themselves by making a sandwich at home.