I agree with you, it is important. The cause of the evolution IS important as is the ‘intentions’ behind the original evolution. Unfortunately once it reaches critical mass, you can’t do anything about it. I think the most we can hope for is that society feels some shame.

However, it’s generally gamers that user the word gay to mean lame. I am pretty sure that there are kids out there that play videogames that don’t even know what homosexual means but use the word gay to mean lame. Once the second generation gets involved all causes and intentions you had in the original evolution are a step removed. I am not sure if this makes it ok but I when it gets to this point, the users of the new word are not to blame anymore…?

I agree that blindly applying political correctness is not a good idea, and artificially trying to stop language evolution is silly (e.g., in France they are very busy with replacing English words by French words).

However, the underlying causes for changes in a language is important, in particular for the example you are giving here. Extending the semantics of a word that means “happy” to denote homosexuality is probably not offensive, rather the opposite. However, I consider it offensive to use a word that is a synonym for “homosexual” for lame or bad things.