Agreed. And by the logic whereby everybody over a certain age is more likely to already have HPV if they were "active", vaccination should be even more recommended to people >45 who start dating again after a monogamous life, right? Because the assumption would be that they don't have it yet, and they are now starting to have sexual encounters with people who are more likely to have it.

More couples are divorcing after age 50 than ever before, so this is not just abstract theory.

Also last time I checked the statistics for HPV strains like HPV-6 or HPV-16, only 5% or less of males were infected by that specific strain. So on a single-strain basis it's not quite "you probably already have it". Cumulatively, it is no doubt higher considering all strains, but the argument against vaccination for all strains on the basis that recipients may already have a few of those strains seems flawed.