I'm not sure this is settled fact at the moment. There are known variants which have shown to reduce the efficacy of at least some of the available vaccines.
The danger isn't from the individual unvaccinated person, it's from pockets of them creating a reservoir of the virus from which new variants can develop. Strong arming people into being vaccinated is the stick with which to try to limit these reservoirs.
Personally, I'm comfortable with limiting peoples ability to attend mass events (which are elective and for entertainment value only) in the tail end of a pandemic without proof of vaccination, I'm less conformable about allowing employers (outside of perhaps those who work with people who are at risk) to do the same.