That's just it though. We're talking about relative level of offensiveness given whatever situation. What I'm saying is that one isn't objectively more offensive than another. Its a subjective measure, or a general societal one which not all agree with, obviously. Google up a list of epithets for whatever group...then try to list them according to what you think is most offensive. Good luck with that, as pretty much everyone will come up with their own ranking.
I'm speaking more generally than just to the OP. What I have a problem with is this attitude that attempts to excuse or lessen the racism of one term as opposed to another. My point is that its all racism, just the same, and for the reasons already covered the perceived magnitude from one perspective or another isn't the problem. The racism itself is the problem...and racism shouldn't be made into some sort of "hierarchy of offensiveness". Its all just racism plain and simple.