USA always could have; since they're a cable channel, the content they air isn't regulated by the FCC. That said, most cable channels haven't wanted to air "offensive" material in the past because they still relied on advertisers as much as over-the-air broadcast networks like NBC do.

With the explosion in popularity of online-only services like Netflix and Hulu, traditional broadcasters now have to try to go up against the wild-west-style of media production/distribution said companies are giving to consumers as well as networks like HBO still in control of a dominant amount of cable subscriber's attention.