I don't think you have the option to say "this app needs Read and Change for just this one domain," it's pretty much an all or nothing sort of deal. This one uses it to edit the page on YouTube, so it has to require it for all.
Now that I look, it's probably a misunderstanding most of us have because of the lack of granularity in Chrome extension permissions: http://lifehacker.com/5990769/why-do-chrome-extensions-need-...