In essence, Discord's staff enforces a hidden layer of moderation behind the scenes. They contact server owners in private and point out individual members' faults and list exact words that are to be removed. In this way, server admins are encouraged to overmoderate due to the obvious imbalance (risk of losing an entire server vs losing a few users), yet they have to take flak from individual users.
I've seen server moderators removing completely legit messages afterwards and they've openly admitted that they can't risk someone perusing the chat history for ToS breaches, screenshotting individual lines of text and sending them to Discord abuse team, because Discord does not care about context, only actual words (see their anti-reclamation policy - even black hip-hop artists have been deplatformed for using the well known mother of all bad words in a positive context).
On a hundred of IRC channels (which had mods) over many years I had like 3 such interactions (and I have to flex to remember). On discord it was 50% in a month.
discord make people very very attached to their virtual space. They craft it, install emojis, makes per room rules, lots of decisions .. it changes how you connect with others, very defensive by nature.
This only applies to partnered and/or verified guilds. All other guilds are only checked on user complaints and otherwise unmoderated (bar the explicit content filter, that applies at the gateway level, before the event gets propagated) by Discord staff.