While our line for once you've freed enough slaves to get told the code is filtered to the Khajiit local, the dialogue for if you ask about it before having freed 20 slaves isn't. That means any non-vanilla Khajiit says "The beast-folk tell of abolitionists acting under that name. Perhaps you should ask them."

Incidentally, the same is true for when a slave asks you to free them and you say no. Vanilla Khajiit will reply "%Name is so very sorry. Please do not punish poor %Name.", but all other Khajiit will get the default "I am sorry. Please forgive me." line. That's a more minor inconsistency though, and the vanilla line isn't great anyway.