This was the initial message to me.
He was making a joke about Gilligan’s island. Duh.
Not an "explanation" as claimed, but an insult and sarcasm which clearly calls someone an idiot or ignoramus for not knowing some reference to a decades old TV comedy.
Look up the meaning of "Duh". Do you consider that humor? Maybe you're then one with a genetic defect. Words mean things, and if folks don't know what some words mean, then maybe they shouldn't use them.
If you have to explain you’ve already lost.