Why?
Because they try too hard, since their main objective is not to be a good game.
It's like reading a novel and immediately noticing the story is just some thinly veiled bullshit so that the author can vomit their own personal view of the world. It makes you lose interest real fast.
You might be exaggerating just a wee bit. Oregon Trail is the epitome of an educational game with lasting popularity, having been around pretty much as long as PCs. There are others -- Carmen Sandiego comes quickly to mind, and arguably even Kerbal Space Program. I'm sure some actual searching could compile a decent list.
Imagine playing within the parameters and finding a combination that brings unexpected results. It's probably harder to design than a standard game, but I think there's potential to have something pretty entertaining otherwise.
Seeing a planet on the map appear close but be invisible, then turning into my whole view really helped me grasp the distance between bodies in space. And KSP is scaled down!
Reading about stalls helps but crashing the tutorial Cessna twelve times really helps you understand what a stall is and why it happens.
You take that back, I loved educational games as a kid! There were indeed plenty of crappy ones out there, but some were really well-made. For example, Pink Panther's Passport to Peril was a charming point-and-click adventure that taught you about cultures in other countries.
There's a small cult following in the Netherlands for these types of edutainment games and a small group of people have set out to archive all of them: https://nationaalarchiefeducatievegames.nl/
The protein folding games paved the way to AlphaFold.
All educational games and all PHENOMENAL.
It taught me a lot of (simplified) country locations and population sizes.
I'm not sure I agree with that, but that's how I understood parents comment.
Cue John Galt's 100-pages monologue at the end of Atlas Shrugged.