I understand where you’re coming from, but the same argument was, and is, made when defending the usage of the word “Gay” as a general disparaging adjective. In a way, the people making that argument, and you when making yours, are right in that many or perhaps most people don’t mean anything sexual in using the phrase¹. But this does not mean that it should therefore be OK to call something “Gay” or labeling a person a “Wanker”. Using those words in a disparaging fashion does lead to a normalization and tacit approval of homophobic and sex-shaming attitudes, respectively.

① I once saw someone trying to establish the term and spelling “Ghey” as a non-sexually associated disparaging word.

At the same time, language changes all the time. It didn't mean the same thing when my kids called something "radical" as in my day. Modern culture has a way of burning up useful words, when they become PC unacceptable. Remember when "idiot", "moron" and "retarded" were technical terms with no emotional baggage? No? You were born too late for that.

Its probably different when words that used to be disparaging become less so (wanker, gay). Because there remain a generation that are still offended by them, we should probably lighten up on them especially in mixed company.

> Because there remain a generation that are still offended by them, we should probably lighten up on them

You’re missing the point. That is not the reason. The reason why one shouldn’t use the term “Gay”, even if one doesn’t mean anything actually homophobic by it, is that by using the term, one encourages actual homophobes and reinforces their belief that their hatred and/or fear of homosexuals is normal. You might think that everyone who hears you knows you don’t mean “Gay” as a homophobic slur, but I can assure you ­— you would be wrong.