1. You wrote that Cultural Appropriation is stupid. You do understand that what you're saying is that it's stupid to for the "majority culture to adopt elements of a minority culture". I think you meant the opposite of that. Being OFFENDED at all Cultural Appropriation, is stupid, is perhaps what you meant.
2. You apparently do not understand why some people take offense at cultural appropriation, because you offer up that their reason for appropriation the culture may be out of appreciation. You can appreciate a culture and appropriate it, and still offend those types of people for entirely valid reasons.
This has nothing to do with why some people are offended at cultural appropriation, meaning to me you don't understand the issue to begin with. Aside from getting the definition backwards in #1.
I think you need to get gud before you try and tell anyone what's stupid or not.
As to SJW nutters being hyper offended by any/all perceived forms of cultural appropriation. Yes, they are stupid. And yet there are some rare instances where cultural appropriation is unseemly and potentially offensive. This all goes back to the actual definition, that involves majority vs minority...majority sometimes has trouble empathizing with the minority, and really cannot understand that perspective. Hell, some people can't even understand basic definitions and word usage, go figure.
Besides, why do you care what SJW nutters think? Triggered?