These extensions you mentioned are written that way. It's possible to make light-weight extensions that load and work only on demand with the current Chrome extensions API, but the authors either couldn't do it without crippling the overall functionality or simply didn't know how it's done. 

The problem with your suggestion to run all extensions on demand is that it's not universal because some Chrome API functions simply won't work. I agree, though, it makes sense to allow users to specify which sites can run a particular extension's *content script*, but only an extensions API developer, rdevlin@ most likely, can tell whether this is even possible.

tomakali@ Thanks for the issue.

From the original comment, looks like this is a feature request. Hence marking this as 'Untriaged' for further updates from Dev.

Thanks..

[Extensions Triage] As c#2 mentioned, it is possible for extension devs to write extensions in a way that they work only on user action on a page (See for example the activeTab permission - https://developer.chrome.com/extensions/activeTab). Also see "host permissions" ,the css matches property and "optional permissions", which allows developers to specify which pages to run an extension on. There is also some work ongoing to make this simpler for content scripts.

I'd suggest filing these bugs with the extension developers. In case, you discover that more can be done by the Extensions Platform itself, please reopen or file a new bug.