From the article:
"I'm not sure that this doesn't slide through the cracks in the Hatch Act," Bickers said. "The Hatch Act isn't about political activity it's about partisan political activity. Since this is a ballot initiative, and there's no party affiliation attached to it, that part of the Hatch Act probably wouldn't be violated."
If you want to maintain that this is really about Republicans and Libertarians, then it is partisan politics, and they are clearly in violation of the law.
Since the Libertarians are more a circus act than a political party, I'd say you wouldn't have much of a case.