My understanding is that it potentially isn’t illegal, because you weren’t being paid to vote explicitly, and weren’t being paid to vote for a specific candidate for sure, but you were (supposed to be) paid to sign an agreement that you would vote, and I think it also said you support a certain candidate but I’m not totally sure on that.

Basically, he was paying for people to say they’d vote (maybe for a certain candidate) but legally that wasn’t actually required, so possibly barely skirts the law if a judge is being very generous to him.