I’m just gonna quote Grammarist as they explain such things for a living and as such do it better than I could:
To speak truth to power means to demand a moral response to a problem, rather than an expedient, easy or selfish response. The phrase speak truth to power carries a connotation of bravery, of risking either the status quo, one’s reputation or livelihood, or the wrath of the person one is confronting.
Are you unfamiliar with the expression, pretending that AIPAC aren’t powerful or pretending that anything AOC said about them isn’t true?
Expression
I’m just gonna quote Grammarist as they explain such things for a living and as such do it better than I could: