> But moderators frequently intervene, delaying posting by days or weeks, reclassifying papers or even outright rejecting submissions.

Definitely not my experience. I haven't posted to arXiv in a while now, but I wasn't even aware a moderation queue exists -- none of my papers were delayed, reclassified, or other...

EDIT: I see the article provides a few examples, but then they also provide numbers: "At arXiv, roughly 6 percent of submissions receive a hold, and about 2 percent are rejected." -- 8% of heavy-handed moderation intervention wouldn't qualify as "frequently" IMHO.