Broseph saidMy dad too (and now my mom). It also started with Limbaugh in his car. Huh.
Me, too. And I'm not talking about my parents, I'm talking about ME listening to Limbaugh.
It started when I had to drive long distances to visit US Army Reserve Units, often in very rural areas like in Oklahoma. I'd get a rental car from the nearest regional airport I flew into, and all we had then was conventional AM/FM in cars, not satellite that I listen to now.
Reception was poor, the music poorer and full of static. But talk I could hear well enough. And there was Rush, everywhere I drove, and better than the Christian preachers screaming hellfire & damnation, my other option.
And he sounded sincere & reasonable, at least back then, and so I listened. Except, when I thought through what he was saying it was full of false reasoning, and all kinds factual and rhetorical flaws. I finally stopped listening and had to be content with CW caterwauling.
So that car radio exposure to Limbaugh actually turned me against him, rather than becoming brainwashed. But I believe a lot of people do view radio & TV personalities as authority figures, and turn-off whatever critical thinking skills they may possess. And then the brainwashing commences.