It’s about what you want to tie to which system. Let’s say you keep some data in memory in your backend, would you forbid engineers from putting code there too, and force it a layer out to the front end - or make up a new layer in between the front end and this backend just because some blogs tell you to?

If not, why would you then avoid putting code alongside your data at the database layer?

There are definitely valid reasons to not do it for some cases, but as a blanket statement it feels odd.

Stored procedures can do things like smooth over transitions by having a query not actually know or care about an underlying structure. They can cut down on duplication or round trips to the database. They can also be a nightmare like most cases where logic lives in the wrong place.