I don't know how it is elsewhere, but where I grew up we had minimum word limits on pretty much all essays. Doesn't matter if you can say what you want to say in 6 sentences, you need 4000 words or 2 pages or whatever metric they use

Oh, of course. Length requirements are important, for the reasons I explained up-thread. However, if teachers accept any old thing ("padding") to reach the count, then that metric is arbitrary, which (justifiably!) makes students cynical.

If a student can say all that they want to say in six sentences then they need to learn more about the topic, and / or think through their opinions more deeply. Teachers who do not take that next step are bad teachers, because they are neither modeling nor encouraging critical thinking.

In some places the majority of teachers are themselves incapable of critical thinking, because those who are leave the profession (or the locale) for the reasons in my comment above.

[Edit to add]: Please note that I say bad teachers, not bad people. Same goes for students / citizens, as well. The ability to think critically is not a determinate of moral worth, and in some ways and some cases might be anti-correlated.