The band tweeted about the documentary earlier today, claiming they only just learned about it and that they didn't approve the song's usage. Subsequently, the documentary responded to the tweet and wrote that the song was approved by Real Estate's label Domino. See the exchange below:
Haven't seen the movie yet. Found out about our song being in it last night from a friend, and while I do think it's a pretty funny recontextualization to use our song Horizon in a doc about flat earthers, no one in the band approved it.— Real Estate, band (@realestateband) February 23, 2019
Thanks for the info! We're looking into it on our end.— Real Estate, band (@realestateband) February 23, 2019
Pitchfork notes that the film's credits say the song was licensed from Real Estate's label Domino.
Listen to "Horizon" below. Behind the Curve is on Netflix now.