The best documented reason would be the ongoing replication crisis https://en.wikipedia.org/wiki/Replication_crisis

Aside from that, focusing on quantity of papers published has incentivized publication of papers that don't significantly increase the store of useful knowledge to humanity, and function as a bit of a haystack to obscure actual useful results

Additionally the 'publish more papers' culture creates other moral hazards, like: 1. Cabals of reviewers who work to help publish each other without regard to the validity of the papers published. 2. Making authors who work for a long time on tougher science have a worse scholastic reputation than those who work to publish a large volume of insignificant papers. 3. Incentivizing p-hacking and alteration of paper scope to salvage insignificant/negative findings.

As a practicing scientist I can't say I disagree with the original statement. Most publications are the bare minimum to get past peer-review to add another line on the author's CV. This is incentivized by academia and the whole "publish-or-perish" attitude so early-stage researchers are expected to pump out a certain number of publications otherwise they'll be out of a career in 3 years.

It's anti-intellectual to blindly assume that the majority of papers published right now are high quality.

This. Journals aren't science. They aren't even good for science. They create the wrong incentives for scientific publishing and are a primary driver of the replication crisis.

Open forums with science publishing for the sake of science should be the direction of travel, but we see a trajectory towards gatekeeping infected by corporate profiteering.

Same with assuming that prestigious schools are more likely to produce amazing research. I have found the absolute worst papers from otherwise respectable ivies. A case of someone buying their PhD, I assume.

I don't know if their argument of "quality over quantity" can be interpreted as anti-intellectual necessarily. If anything, I think that can be seen as pro-intellectual and against stats/funding-chasing.

Publish or perish encourages empty nonsense papers that dont add much value but do add noise.