Firefox's answer, at the bottom of the article, smells like pure BS to me. Disabling an extension with something like a full browser-modal pop-up to warn users of the possibility of an untrustworthy Extension? Sure, fine, whatever, and maybe make that warning capable to be disabled by default, but why make the decision for us - silently - that Extensions are not to be trusted? Do we trust the website that asks if we pwetty please should allow the showing of ads, or maybe the malware provider that please should just disable all security Extensions and allow their malicious code to run, if you would be so kind?
I can think of one use for this: to disable malware to substitute clicking on a link to install your Extension of choice with one of their choice instead - although isn't the Extensions store already treated specially by default anyway?
Otherwise, I don't favor taking control away from the users. Especially if users cannot disable this new "feature". There is far too much potential for misuse of this.
Which will fragment the Chrome & Chromium-alternative market further, if people cannot trust Firefox anymore.
Which will slow development of alternatives to Chrome.