There are FOUR VERSIONS OF FIREFOX WITH A SWITCH TO DISABLE THIS if you're so inclined. You can use: Nightly, Dev Edition, Unbranded Stable and Unbranded Beta. All of which have a switch that you can set to disable addons signing requirement.
In contrast there are only two versions where this is a requirement, Stable and Beta. If you doubt the usefulness of this you haven't seen a browser being hijacked by malware overriding search results, inserting all types of toolbars and more. This will prevent malware from sideloading extensions. And this is good.
The signing process is not the same as the AMO review process. The process takes only seconds and the signed addon is returned to the developer. They can distribute as they see fit.
Now, lets face the fact: Simple signing process that takes only seconds and will help prevent lots of malware, not the most nasty ones but a huge lot of sideloaded crap. Four versions of the browser for those power users who want to disable this.
Now, can someone explain to me without hate why this is a bad thing?