Understanding rationale behind faith persecution

Because Christians behaved in an unchristian-like way in past centuries towards Jews and others they are now deemed somehow not entitled to defend themselves from persecution, banishment, and massacre.
That is the rationale behind the persecution of faiths and ethnicities in every age. It is historic wrongs that are always cited as justifications for persecution of old foes when the balance of power shifts. Would your correspondent also tell the Muslims in the Balkans that their tears were “crocodile” when Serbs attacked their villages?