It's nerd humor. You're not supposed to find it funny, but nod along approvingly while noticing how awfully clever you are for noticing the attempt at being funny.

Considering that D in "ACID" stands for "durable", it's a pretty sloppy joke.

It's not a great joke, to be sure. But the essence of it is that it's a good database, by relevant but inappropriate standards.

Insufficient/incomplete rather than inappropriate, perhaps?

The problem with the joke, as I see it, is that it only works with a colloquial definition of ACID. If it worked with a formal definition, it would be funnier by having a twinge of insight.

It's as if the joke requires two steps away from reality: first to apply the definition to a domain where it doesn't apply, then mis-reading the definition to make it fit. Having to go two steps like that spoils the feeling of insight that makes a joke like this work.

The article doesn't belabor the gag, which is a point in its favor. It has to hit you with its punch line and then quit before it wears out its welcome.

"Its not funny" says the one guy in a room where literally everyone else is laughing and riffing on the joke.

Your humor unit might be defective.