It's indeed somewhat weird from a user's perspective. Not sure this can be changed though. Those extensions in your screenshot use persistent background pages [1] that start just once per browser lifetime, and in current implementation of the extensions API it doesn't matter if you close all windows of the initiating user profile. A modern and preferred approach is to use a non-persistent event page [2] instead, but not all extensions can utilize it, and in many cases the authors just don't care. Note, there's an additional background permission [3] that starts an app/extension on logon of OS and keeps it running even when all browser windows are closed (at least in Windows OS).

  [1]: https://developer.chrome.com/extensions/background_pages
  [2]: https://developer.chrome.com/extensions/event_pages
  [3]: https://developer.chrome.com/extensions/declare_permissions#background

Assuming that none of your extensions require background permission then unloading profile would save some memory and it is definitely a good thing. However, currently Chrome never unloads profiles and implementing such a thing is a significant project.
There's a similar issue 491430, I'm going to close this one as a duplicate.