I don't see how that could be the case at all, even anecdotally, as the fighting in Massachusetts was done by mid-June of 1775. That's like having the impression that WWII was fought in Hawaii.
Actually, it was done July 1776, or just before (can’t recall the detail, but they moved out before August).
It doesn’t matter what the facts are. If people aren’t given all the facts, and are mostly given impressions - well, their impressions will be less than factual.
Surely you’ve heard the saying “if you repeat a lie long enough, it’ll be true”.