It's not simply because malcious developers exist. It's that we've collected data showing a large and quickly growing percentage of our users have been hit with forced installed extensions that invade privacy and worsen the browsing experience, often along with native "protector" software that attempts to keep those extensions installed even if users try to uninstall or disable them. While we can't share exact numbers, we have stated publicly that this has become our #1 customer complaint; if you spend a little time browsing this forum you'll see plenty of evidence of this.
So we felt we were caught between 2 terrible choices:
1) Implement this more restrictive policy that we hope will help a large percentage of our user base remain free of invasive extensions, but be an inconvenience to a smaller but definitely non-trivial number of more sophisticated/technical users who want to run extensions not installed from the webstore.
2) Keep the current behavior, avoiding causing problems for more advanced users, but leaving a large portion of the user base afflicted with invasive extensions.
In either case, plenty of people were going to be upset and unsatisfied, but at the end of the day we decided to try and do what we thought was right for the largest number of users. I understand that as an individual it may be hard to see things from this perspective, but I wanted to at least share how we're thinking about it even if that doesn't reduce your frustration about it.
While we don't always get things perfect, we do have some processes in place in the webstore to prevent or take down extensions with abusive practices, but our ability to detect and prevent this for items outside the webstore is much more limited. Again, I'm really sorry this is frustrating for you folks who've posted as such so far. Here are a few options for you:
-If it is an extension you wrote yourself, you can upload it to the webstore and publish it in a "hidden" state so that only people with the link, or people in a set of trusted tester users, can install it.
-If it is an extension from a 3rd party software company, contact their support to point them at our blog post
and ask them if they can migrate their extension to the webstore.
-We are only enforcing this policy on Windows beta/stable channels, since that is where the problems are. More advanced users may wish to try out the chrome developer or canary channels (the canary can be installed side-by-side with other channels of chrome). Also I should note that we aren't enforcing this policy for chrome apps or themes, nor are we enforcing it for extensions on MacOS, Linux, or ChromeOS because we don't see anywhere near the same level of problems on those OSes (obviously switching OSes is a big deal and I don't mean to suggest that you should consider this, but I just wanted to make sure folks already running those OSes know that the policy doesn't affect them).