You've made one strawman accusation, and sure, people polarized that specific way (insisting only things worth doing are worth making reusable) are often doing bad things.
But I see plenty of anti-intectual anti-whatever attitudes founded in other forms of disdain. And I think grug reflects a broad/broader spectrum of negative biases.
One example, I've had an incredibly hard time getting folks to switch from dirty cobbled-together-with-StackOverflow shell scripts to Ansible, which is a just more sight-readable consistent experience. Or to zx or anything not just badly written shell scripts no one collaborates on.
People swear worse is better, are YAGNI (you ain't gonna need it) up the wazoo against 90% of everything. I think grug picks a lot of things to bash on, and a lot of devs do to.
I adore simplicity, but I find it challenging & long & arduous to hammer out of things. It's not fast to produce, or low thought. It's not made by resolutely sticking to lo-fi paths & mentalities.
We do need to be aware of the hazards at the other side, of ridiculous complexity & absurd/unnecessary systems engineering: yes! And I think grug offers some good almost-koans to reflect on, illuminates real hazards well. But I also think it's actively harmful & pernicious to put grug-brainedness on a pedestal, to go about actively disbelieving against any possibilities that might possibly be done simpler.
We seem to agree that simplicity takes iteration. Grug presents it as "oh I'm just dumb grug brain, I dunno" but in practice there is a lot of infighting in tech, and those who insist too loudly on aiming too high are not even IMHO as dangerous as those too loudly insisting on too low. We have to keep engaging possibility from all sides, & keep finding out what balances do work.