Ad fontem... a nice term. I like it.
Lark, I have good news and bad news. Good news is you don't have to impress them or change them. They have held their views long enough that they're deeply entrenched. External persuasion, for the most part, only works to move someone's opinion slightly. For someone to make a major change to their views, they have to own it as their decision.
Bad news is it's on you to try and prevent them. The young and searching are the ones who are really up for grabs.