>The reason is to actually to build the so-called "herd immunity" I think. Same thing with antibiotics (no need to give evolutionary "ammunition" to virus and bacteria if we don't need to).

I don't think that's the right comparison. Herd immunity refers to stopping a disease by spreading by making enough of the population immune so it can't spread. It doesn't have anything to do with evolutionary pressures or superbugs, like what you're alluding to with your second sentence.