Where did this crowd of "Hitlers" come from?

We hear it all day. all day we learn that Trump is Hitler, Kaczyński is Hitler, Netanyahu is Hitler, Marine Le Pen is Hitler, Orban is Hitler, etc. quite a few these "Hitlers" in today's politics. The full crowd. And this is truly just 1 and the same paranoia and propaganda manipulation! This "reductio ad Hitlerum" has been going on for decades and growing.