Tom is right. Frameworks like Angular and Ember are bigger because they offer many more features out of the box.
Angular 2 versus React: There Will Be Blood
Cory House

I’d go with less features and leaner codebase. At the end of the day I can imagine that Angular 2 project would load even more JS in the end. Those modal popup windows aren’t in the framework. As well as tokenizers/tagging and a dozen of other helpful plugins/modules.