A better argument is that every army that ever conquered Britain integrated their own vocabulary into what was already there. It wasn't an act of butchering by the natives.
English is a mongrel language, but it became so through acts of violence.
Well, England did it’s fair share of conquering too, so it would be safe to assume that they also picked up verbiage from the conquered and integrated into their own, and/or the conquered picked up some of the English and butchered it some more.
But yea, were all mongrels and mutts.