I don't like the "batteries included" metaphor because it implies getting batteries is hard. Yes, Angular ships with routing but thanks to the node ecosystem adding react-router is a one-line command. The hard part is learning the routing API which you have to do either way.
"batteries included" means that the software itself has everything you need to get going. It's not that it's hard to get an individual component, but now you're relying on a third party component and potential issues with random configurations etc. It takes some research and effort to figure out that react-router is the best module among the options for routing.
