Stepwilk. Please don't be offended by this. It is an English expression that has been around for centuries, and has absolutely nothing to do with race or colour. It simply refers to a garden tool, and I am sure someone knows the history of the expression better than I. It may be something different in your country, just as 'Fanny' to you has a totally [and to some people,rather obscene] meaning over here. I am sure GQ2 was tongue in cheek, because he knows the dog cannot have it's original name in this day and age.
At the same time, history cannot really be changed, and I wonder if anyone over here has asked any gentlemen of colour if they would be offended by using it's original name?
Certainly my coloured ex son-in-law would see no offence in it whatsoever.