VPN to production and same hostname for dev and prod?
As well as pretty much every other privilege they don't legitimately need to use on a daily basis -- which, for prod, should be most of them (quite possibly including "delete").
If or when they really need to delete a ton of rows all in one go, they can be given a (temporary) set of credentials that they can use to do that, once, and which are then revoked immediately afterwards -- after another set of eyes reviews the script they've written to actually perform the operation, of course.
Basic best practices aren't difficult or some secret thing that only the experts know about. It is necessary to actually implement and follow them, however!
Sure, it can be a pain in the ass sometimes. Will it be worth it when it eventually saves your ass one day, "after a couple of glasses of red wine"? Absolutely.
There is a whole lot of things that could be applied which would have prevented this, before needing to hire a separate server admin as an interface to the production database. :D
I'll give them the benefit of the doubt and suggest that it wasn't the case and that it's unlikely that a dev or OPs person was tunnelling through a bastion of some kind to run the script.
If they pulled their credentials from a store and populated the config object that way, it's very possible someone actually loaded the production credentials by mistake into the development secrets file. The CI/pipeline system has permissions/network access to deploy to any environment, hence how it ran the script to drop the table.
I'm purely speculating another alternative to the much worse case of the tunnelling scenario outline.