If you don't mind its only because you don't understand it?
So if we don't agree with it we are just not as clever as you? And we don't agree with you about advertising we are even stupider and not worth your arguments? Way to win an argument there.
McDonalds = corporate business in a capitalist world.
Mumsnet= also business in a capitalist world.
If you don't like them advertising with whoever they like, go ahead and boycott, and piss off. If you are that concerned about McD's, go actually do something with your principles and stop bleating on here.
If you're really an old style lefty go wave your placard outside McD's and try to resist a chicken nugget.