Though this kind of thing will generally be removed by the extension block list, not merely blocked from working on some domains.
That makes zero sense from security perspective.
It would be like asking antivirus to only let virus access D:\ drive...
But even in the very best case, it's yet another custom "premium support" feature either way, like the Public Suffix List. They should push for standards instead, these kinds of things are always leaky and sometimes dangerous.
Anyway. I just meant that extensions are not trustworthy just because they're installed. Malicious vectors exist, and protecting people from themselves / them understandably not being an up-to-date expert in all things tech by the millions-to-billions is largely a good thing.
It's up to another layer of security to help the user not install extensions (or any other software) that they do not want on their machine.
This security is a farce anyway. Firefox is installed in the user profile so any sufficiently advanced malware can just patch the firefox binary and embed itself in there or disable this nonsense. The extension shenanigans is just done to take away user control, with the excuse being to protect users from malware.