I'd be more suspicious of a person coming to my door purely just to educate me on cool science things. I wouldn't be able to shake the feeling that he's trying to sell me something.
At least with religion I know their game and I know I'm not interested but science that's interesting.
I'd be more suspicious of them telling me life exists on Venus, specifically. Last I heard it was a hot-ass gaseous atmosphere made of acid. My money is still on Europa.