I agree, the API should only be loaded when necessary. However, including a "youtube" item in the require.js config does *not* load the API -- it only informs require.js that when a module says it requires the "youtube" dependency, this is how to load that dependency properly. If you want to stop the Studio unit page from loading the Youtube API whenever it tries to display any XModule, you want to modify the file `/common/djangoapps/pipeline_js/templates/xmodule.js`. You'll notice that that file includes "youtube" in the list of dependencies.