It's OK not to know the hurtful etymology of something; it's also OK to be hurt by it and to educate those who don't know. To me the best way that this goes is that 'hurt party' kindly explains to 'unknowing party' who, in turn, kindly agrees to abandon hurtful term, and everyone moves on with life. What often happens however is either that unknowing party pushes back (often aggressively), imagining their rights to have been infringed, or else hurt party opens the discussion aggressively, perhaps anticipating pushback before it materialises, or perhaps just already upset at having long been on the receiving end of hurtful behaviour but previously unable to speak up, often because of systemic bias (think: oppression of black people in 1950's USA just as one example among many). And then we get a super-heated culture war, which is really just mixture of people wanting to be heard and understood, and some people deliberately stirring the pot for ulterior reasons.
The answer to your question is thus another question - do you care if people suffer because of the actions of others? If you do, then try to be kind, and remember that being kind sometimes means making minor sacrifices to bring greater benefit to others.