Liberalism can rather easily become a form of fascism if the thought police are given too much rein.

When people are attacked for their political or social views and forced or coersed into following the party line.

When freedom of speech and thought are proscribed, and people painted as morally bad for holding differing views.

This is exactly what happens here on many subjects, if one does not toe the "liberal" line, one is rarely opposed by reasoned argument, but rather by a torrent of personal abuse

Liberal or illiberal? Fascist or democratic?