I agree with you to a certain point (bolded part). However, Mona is somewhat of a "celebrity" or at the very least a person who others may look up to so I think that it's warranted to call her out on this.I am in no way anti-vax and I think vaccines are one of the most important (though eroding) infrastructures of public collaboration. I also think Mona seems to have extraordinarily vapid takes and to be the kind of person I find insufferable i.e. who thinks they alone see The Truth.
That being said I do not think that collectively dunking on people who are anti-vax is the most effective way to change opinions (and many people I know who publicly dunk on anti-vaxxers seem not to have read anything on vaccination themselves). More of my ire is directed towards the private pharmaceutical industry which does in fact engage in many practices that reasonably warrant suspicion and distrust (though that of many anti-vaxxers often seems ill researched).
Whether or not this will change her mind is up in the air but I think that she's a spiritual person and they typically hold the same/similar beliefs as her.