Sorta right on the first count. Waaaaaaaaaaaaaaaaaaaaaaaaaaay off base on the second count.
Part two first. Moxie's is delicious. Period. True, it's an acquired taste not everyone has the good sense to acquire. Sorta like feta cheese, black liquorice, or the vocal stylings of Tom Waits. Purely for the initiated.
As far as it being a Mainer thing, that's more a matter of cultural appropriation.
Originally, it was called Moxie Nerve Food. It was a brain stimulant, one amongst many of the ole tyme patent medicines of the gad light era. Think along the lines of Dr. Hofstetters Celebrated Stomach Bitters or Dr. Kilmer's Swamp Root Cure for Liver, Kidney and Bladder Woes and you've got the idea. (As an aside, the aqua bottles were manufactured at the Lyndeborough Glass Works, which was over near Peterborough).
But with the passage of the FDA in 1906, Moxie, Coke, various sarsaparillas, and others sought to rebrand themselves as soft drinks. Maken the transition from brain tonic to "soda pop."
Which is why us of a geezerly mindset still call carbonated softdrinks "tonic." It's what they once was.