That is correct unfortunately, due to a API limitation. https://lua-api.factorio.com/stable/prototypes/ContainerPrototype.html
I'm looking at other solutions for the time being, but they will be in future updates. It's in my plans to add some custom scripting to allow rotatable containers, but that will take a while. Thanks for the suggestion though, it's been thought about! I've just gotta work on main features at the moment.
