I think that's the point. It's like deep fried memes. It's about stupid absurdity. Memes being funny isn't always a required factor for their enjoyment.
It is stupid and unfunny. Its the kind of thing 13yo boys laugh at. Problem is we grow up, get soul crushing jobs and one day we're at the Deli counter and ask for about half a kilo of ham, the guy bags it and puts it on the scales and it comes to 420g and you grab some other stuff and go to the checkout and the total is $69. You realise 13yo you would have loved that, realise how little silly joy there is in your life now and contemplate washing your mouth out with buckshot.
I think some people miss the point. Number 69 is not funny because of sex, it become funny because we like absurd stuff. Whenever I point out "Nice.", not in a slightest I think about sex position, or I am being horny, it's just 'funny' on it's own.
My hard sci-fi universe = "the year is 420,421 AF (After Fusion)"
Why? Because it is easy AF to remember, and I don't even smoke. Like, let's start out with this, so you know what to expect. This ain't no authoritarian laser dildo wand flick here to propagandize cultural exceptionalism.
All these internet jokes are not really funny after a while, but they are just easy. Someone said 69 somewhere, answer with nice, wow, comedic genius over here. Hey guys, i just thought of something deep and funny: the existence of a FUN house imllplies that there is a NOT SO FUN house out there. Isn't that insane?
Or someone asking a question and you just answer it with "yes" HAHAHA how funny and quirky is that?