it crushes me when misappropriation strips meaning from foreign words and recontextualizes them as some new slang... to incorporate "habari gani" or "as-salamu alaykum" into foreign languages doesnt immediately qualify it as slang, that's just how language works in multicultural societies.

This is a great point. And when French in particular adds English words, which it does often, it's not called slang. And French is packed with Arabic words that are basically standard now.