b/c it fits your warped sense of humor? while i don't much like wearing pink, i'm a complete advocate of gay rights, have had gay friends, and make damn sure my gay students don't get fucked w/ - but i still say gay, b/c that's the culture i grew up in, and if in my own head at least its meant to be ironic, that's good enough for me
i have learned to avoid describing things as retarded though in the presence of the special ed teachers i work w/, after an unfortunate incident my first year that said, a special ed teacher i frequently clmib w/, and even happens to post on this board once in a blue moon, uses that mean, mean word all the time in jest
if i'm around someone who takes any of the words i'm wont to use offensively, i usually watch my language if i like them, or increase the frequency to drive them to fucking distraction