Cracker is offensive and most people would get pretty pissed off if a non-white said it to you, but I don't think you can compare the words. Does the word Cracker have over 200 years of enslavement and murder behind it?
How can you not understand it? And probably the majority of black people tend not to be ok with anybody saying it.
I simply can't. If they feel so offended why do they keep using it themselves?
It's also fun to watch them get so angry and combat ready when they hear it Most white people just talk back.
Those friends of your would be called sell-outs by the very same people who use the N word. Personally I would rather be a sell-out and not have my ethnicity thought of as some sort of caveman because I can't find more appropriate diction.