Tenured - they can't fire him for what he says.
He had to sue to get tenure, IIRC.
Which is not to say that they (UNC Wilmington) did not give it their 'College Best' to malign, deprecate and make his life so miserable (no promotions) that he would leave. Professor Adams fought a 7 (seven) year legal battle with the University (and won) to allow him to be promoted on his normal career track without regard to his 1st Amendment-protected writings and speech.