> There should be a name for the phenomenon where people upset about some injustice pick the least plausible example to use as the cause celebre of the injustice.

Perhaps 'The Toxoplasma of Rage'? See https://slatestarcodex.com/2014/12/17/the-toxoplasma-of-rage...

Or you might like https://slatestarcodex.com/2017/04/12/clarification-to-sacre...