Just guessing, but I would say that's because "git" is only derogatory in British English, and wasn't popular (if even existent) in American English until it's use as the name of a DVCS.
I agree. While I'm training people on git at work (in Seattle), they often look up the term and point out the definition to me. I then direct them to Linus' intention, for it to be "a stupid content tracker".