It doesn't. But there are specific settings required for making and maintaining indexed views, and this happens to be one of them.

If you change the setting before trying to create the view, that in itself would already fail. (Or, to be more precise, creating the view would succeed, but creating the index to convert it from a normal into an indexed view would fail).

The reason for this limitation? (Puts on speculative hat) Many settings are discouraged anyway, and I guess that MS decided not to put in extra engineering effort to support and test indexed views (and several other features with similar limitations) under all those settings. So they simply forbid them.