Wow, this could not be further from the truth. Angular is much more similar to Rails than Drupal. Like Rails, it magically takes care of some of the more routine and annoying parts of front-end development like DOM manipulation and testing, but beyond that you're just writing javascript without having to worry about making sure your views are being updated. To extend the analogy I would compare Backbone to Sinatra. It's much smaller, allows the developer to make more choices, but takes care of less details.
So if you prefer Sinatra over Rails, you'll probably prefer Backbone over Angular or Ember. If you like all the magic Rails has to offer, you're probably going to feel right at home with Angular. But comparing Angular to Drupal is ridiculous.
Actually, I would compare AngularJS to Node's Express or Ruby's Sinatra. Because by and large it's actually a set of highly reusable and composable blocks that make very few assumptions about what you're trying to do (aside from something vaguely DOM related). It's a fairly pure look at the MVVM metaphor and does not even assume you're trying to do CRUD or RPC or whatever. Heck, you're not even tied to using client-side routing.
Please don't compare it to Express. Express is a beautifully simple, and clean framework that strives to always have the least magic possible. You can see that goal reflected in the simplicity of its documentation as well. You can build on top of it with any other node modules you want exactly because it doesn't make strict assumptions about your code. If you were to compare Express to any front-end framework it would be Backbone.
Angular is not simple in any since of the word. (Especially if we're talking about its documentation.) And it's components are only reusable inside the Angular bubble.
So if you prefer Sinatra over Rails, you'll probably prefer Backbone over Angular or Ember. If you like all the magic Rails has to offer, you're probably going to feel right at home with Angular. But comparing Angular to Drupal is ridiculous.