Of course you can call things over engineered, but seem to want to include questioning the requirements, specifically also those of the example we're talking about.

Once you start that, you also need to stop somewhere. For example, we could even question the need for a door in the first place. Not saying that we should, but if you want to take over defining other people's requirements, you're putting this on yourself.

So if you don't want somebody else to call you out for over engineering somebody else's requirements, where do you stop?

It's not an enviable position to be in. :)