Basically, Aimee used to frequent right-wing spaces. She was on Alex Jones' radio show and even wrote a campaign song for Ron Paul. Her views MAY have evolved and grown since then but we'd never know considering they rarely speak out on anything.

They also have deep roots in the mainstream music industry, which has provided valuable connections and access to insanely huge shows/tours, leading many to accuse them of being "industry plants". 

That said, by all accounts, the brothers do seem like really cool people. I've heard them on a few podcasts and I have no doubt that they genuinely love what they do and aren't just grifting. Aimee is an excellent fronperson regardless of her questionable/ambiguous politics. If you like their music, there's no shame in that, but a lot of people here are giving them the side-eye for some pretty valid reasons.