> Please, explain why this is an unreasonable standard?

Because you haven't described a standard, you've asked for "broad, systematic evidence." What exactly constitutes "broad, systematic evidence"? If we were to provide you with, say, 20 instances of left wing discrimination against the right, would you admit you're wrong? How these conversations usually go is you demand evidence, we provide evidence, you say our evidence is invalid and round and round we go.

This is called "bringing dialectic to a rhetorical debate". You're not arguing logic or facts, you're arguing emotions. If I'm wrong on that fact, please, describe an exact standard that would convince you the OP is, in fact, correct.