The argument brought forth by various people is clear: it's more difficult because it involves effort much more consistently, for a much longer period of time. You don't have to appreciate the argument; of course.

As to objecting to forced medical treatments: while that discussion is relevant to the appropriateness of an (almost) mandated vaccination campaign; it's not related to how difficult it is to diet vs. be vaccinated. The fact that you bring it up makes it look like you've made up your mind on vaccine mandates and aren't considering various arguments on their merits to support a conclusion on mandates but rather the reverse: that you're picking and choosing arguments based on whether or not they support your pre-conceived notion.

Now, that doesn't really bother me, but it does make me curious: why do you oppose vaccine mandates? And why this mandate but not others we've had for decades?