I think you are getting hung up on the names. Not every MVC framework sticks to the same naming convention. For example, in Django, Controllers are called Views and Views are called Templates. Backbone follows a similar naming pattern. Note, Backbone is very flexible on the views part, not enforcing any particular templating library.
As already noted, the logic included in Backbone models is logic that is the concern of the model. A standard relational database, which is a collection of models (tables), typically cares about the type of data in columns.
Logic that would typically go in your controllers (Backbone's "Views") would be things like handling transient session data, checking user state (authenticated for example, although you wouldn't be doing that in js), binding views to models (Backbone does exactly this, managing where and when models are stored/created based on user actions and binding templates to update on model changes).
So, in summary, Backbone actually sticks pretty well to MVC, much better than most server side "MVC" frameworks which are typically really "PAC" frameworks (Presentation-Abstraction-Control).