I totally agree with your opinion, you shouldn't have to connect to FB in order to access a game feature.
I'll pitch this as hard as I can to the team until they change it.
They may choose a more subtle approach to this, for example (and this is just a 1 second thought), players that use Facebook get 10/10 items in the wheel and players that don't will get only 8/10 items, if they want to get the other 2 they will have to be FB connected.
Or they may choose to remove it completely as a requirement for the wheel.
Like @Shai-Hulud mentioned, the purpose of FB connect is mostly for the benefit of the players - they can stay in touch with the player community on FB and with the game FB page (where contests, events, news, maintenance and other stuff are shared) and also it's a safe way to "backup" your data/account.
We'll wait and see what they decide.