It’s not the Twain quote, but it is very similar to an old joke about a bus crash full of black people. Same punchline. I wonder if he is trying to redeem an old joke or is just unaware of it.
To me, this seems about the start of the “normal” run of the strip. Got all the early floundering out of the way and the long-lasting characters start to become refined and defined.
When the lockdown first got going, I started calling it “Netflix and ill.” :)