I have no problem buying products or services promoted on radio, on their merits rather than the hosts' "personal" endorsements or the actors phoning in their phoney endorsements
That's you. You are one person. Advertisers want to reach millions. They are pretty sure their approach of using endorsements will appeal to a large number of people in the target age group. They're paying for access to that audience base, and you're in that base. Advertising in general is a percentage business. You never achieve 100% success, but you hope your pitch will be successful often enough to make the ad worthwhile. Otherwise, they won't do it.