Your website and code is yours. We don’t own it and we don’t want rights that give us a similar level of control.
The “in relation to our service” is the limiting factor here. We can’t just dump your source code online as it would violate that limitation as there would be no relation to our service. But sharing small snippets of code for troubleshooting/debugging purposes could happen, of course.
Also, we could run a promotional campaign with some materials showing “look at what kind of sites people host with us” showing your site. We don’t do this, and if we did I would personally want to get permission beforehand as much as reasonably possible.
And this access is separate from whatever license you may be using to release your content publicly. Whether that’s basic copyright law, some CC license or something else, we have our own agreement with you that we have regarding every site that doesn’t involve us having to keep track of the unique license requirements of each site.