Why is create index grayed out on Views but not Tables?

As above, on Tables it's not grayed out but on views it is grayed out?

Not all views can be indexed, and generally it's not something that's done using the GUI. Here's the documentation describing the requirements:

https://docs.microsoft.com/en-us/sql/relational-databases/views/create-indexed-views?view=sql-server-ver15