Languages change and as said before Gay used to mean happy and wonderful then it changed to another name for a Homosexual and now with it widespread use as a way of saying somthing is rubbish or crap its changing again.

As an aside

for the people who dont like the use of gay to mean lame

the word lame in itself is probably offensive (or was when it was first used) towards disabled people

languages change tbh...

well Im a happy guy, and Im offended that homosexuals have stolen the word gay