I think that there's a significant number of people who didn't do the learning you apparently did, and instead tried a let's call it "vocational" approach. Funnily enough, such approach is at the core of the jokes about a so-called "humanist" studies leading to a job at McDonald's - the difference being that you can usually get by enough to start in STEM fields.

The other group of people complaining about university, to whom I sometimes belong, is grumpy due to how easy it is to be self taught, even if you might miss some of the more theoretical stuff that you won't use unless you work on a harder problem than most software in the world. Sometimes it's not even about education as much as it is about finances - I quite often found myself looking at job ads and thinking "I could do the job right now if I dropped uni, and I would have no more problems with money".