“Eroding mutual tolerance in America”

According to this article, high school teacher James Corbett, found to have violated a student's First Amendment rights last year by disparaging Christianity in a taxpayer-funded public school class, is now urging all “intellectuals” to do what he did and “push back against the ‘right-wing authoritarianism’ that is eroding mutual tolerance in America.” If someone’s eroding mutual tolerance in America, I don’t think Corbett has quite put his finger on the source….