My hypothesis:
The deeper problem here is not the words themselves, and their meaning. Language is dynamic, and words can change meaning over time, sometimes over surprisingly short periods of time. The actual problem is - as I see it - the reasons people use offensive words and insensitive language. Their usage would have origins such as outright racism and xenophobia; fear of behaviour, culture, language, appearance that is outside one’s daily experiences; lack of empathy and a lack of care for others, or outright egoism. And all these reasons can again originate from basic struggles in life, like having problems making ends meet economically, and/or basically just having a shitty life. Or it could be due to indoctrination by parents, family, peers that are in such a situation. In any case, if you see no reason to treat other people decently, you won’t. The only fix I can see is to repair the basic premises of the life people lead, for example through economic safety, good schooling, instilling a sense of community responsibility in people (as opposed to the tendency we see now towards every man for himself), etc. And of course to talk to others using a polite type of language.