Database professionals say, “That’s slow because it’s a size-of-data operation.”
A size-of-data operation is when the database has to write all of the affected data again. What you’re asking for might seem small, but for the database, it causes a lot of work.
For example, let’s say you live in a strict household, and your parents have told us that under this roof, everyone’s hair can only be black, blond, brown, or red. (Don’t blame me. I don’t make the rules. They’re your parents, not mine. Go talk to them. And tell your mom I said hi.)
If your parents