You were never supposed to take it that seriously.
If you were genuinely looking for heartfelt, whimsical pirate adventures, I don't think Monkey Island I & II were the right games for you.
As much as I loved The Secret of Monkey Island (1990) and also its sequel Monkey Island 2: LeChuck’s Revenge (1991), the ending felt a bit like a gut punch.
The whole story comes crashing down in a bit of a Star Wars-y fashion with a “I am your brother” reveal, followed by a shift into what looks like a child’s day at a carnival. I mean, what in the actual...? Why?
It essentially undid all of the original game and the sequel for me, an ending that made zero sense to me and felt forced.
Ron Gilbert never fully explained his original intent at the time and later said in interviews he wanted the ending to be strange and polarizing.
Well, mission accomplished.
Don't get me wrong, I still think they are fantastic games, but that ending still bugs me to this very day.