Hell's Kitchen & the Gay thing

I really, really don't mean to be offensive here, and this is a genuine question. Is shirt-lifter a derogatory term in and of itself (such as nigger is) or is it a "descriptive" term that can be used derogatorily (as can many other terms/words). I guess what I mean by this is that the word 'gay' in and of itself is not derogatory as it is descriptive, although it can be used to cause offense, whereas 'nigger' is pretty much agreed to be offensive in any context due to the history and background of the word. Is shirt-lifter a word like nigger, or is it just another euphemism for gay (such as 'friend of Peter Mandleson' or 'bats for the other side') which are apparantly perfectly acceptable and non-offense in descriptive contexts.