By this logic people are also forced to work for Uber/Amazon/other exploitative employers of low-skill labor. This undermines many arguments against unionization, treating "gig" workers as employees, or in favour of "right to work" laws. Yet the political leanings of those opposed to vaccination are often anti-union, pro "right to work", etc. So this doesn't help illuminate what they mean by "forced", unless this is a framing used out of convenience to justify their opinion in this specific case.