Doesn’t make much sense to me.
In practice the most common use is referring to the purveyors of a meat flavoured substance sold contained in a bread bun.
Given his dietary preference, I can see Sir Paul being uncomfortable with the association.
What girlyman Jacobs's problem is I have no idea.
Obviously, Martin J. Jacobs, President/CEO, Lanmar Inc. doesn’t have a clue what he’s writing about! :-)
A quick google search will show that Paul McCartney’s been called Macca for YEARS AND YEARS in the British media. This person’s jumping on the wrong bandwagon. :-) There’s so many other real reasons to jump on journalists-this one’s just blowin’ smoke.