The poster you just replied to took the words right out of my mouth.
While I agree with you, and not a lot of people seem to disagree here, that vaccinations against dangerous diseases are a good thing, I think over-medication is the bane of our health care systems.
In the Netherlands, doctors have a reputation for not easily medicating people. We're cautious about antibiotics, we're cautious about many types of drugs. The usual response of a Dutch doctor to fever is that as long as it's not over 40 degrees C and doesn't last for longer than three days, it's nothing to worry about. Of course this can be nuanced based on symptoms seen, but you get the gist of it.
This means that the amount of people that develop an immunity to antibiotics and whatnot is much lower than in countries such as Israel and Bulgaria, where people tend to be over-medicated in my view.
To get back to vaccination, I do think it's our collective responsibility to weed out things like polio, diphtheria, pertussis and tetanus as much as we can, not getting flu shots is hardly morally offensive for the reasons already stipulated by the poster above.
In the Netherlands there's a huge debate over religious freedom vis a vis the vaccination of children from families that are religious to the point where they don't vaccinate. I'm going to go out on a limb here and say that it's a collective responsibility to make sure these children don't fall victim to their parents' backwards views.
What you believe should be your prerogative, but as soon as you let it endanger unsuspecting minors your belief should be a secondary concern relative to the safety of those unsuspecting minors.
Either which way, a degree of nuance is called for in any such debate, so I don't think you should make messaging as simple as a blanket statement of "please get vaccinated" any more than you should advise people not to get vaccinated at all.