It kind of makes sense from the perspective of: "if I have a very specific use case of needing a full Route::resource(), it will almost certainly be because I'm building a controller with all of the corresponding REST methods", but I also understand why it can be confusing. The great thing about the documentation is that it's just as open source as the rest of the project, so you are free to submit suggestions/changes in the form of PRs to improve its readability.
For example, since you find it confusing, it's likely that other people will too. Why not submit a PR on the Routing page that says something to the effect of "If you are looking for information about resource routes follow [THIS] link" and link to the section on the Controllers page?