This was exactly the explanation from Mozilla side and it makes sense. The reason for the decision was people telling "my internet stopped working" (white pages) once they've disabled JS by accident.
The manual for my car mentions things that must be done for maintenance. They don't dumb it down. Meanwhile in computer land we hide all options and dumb everything down to "protect" the user.
There is a difference between being easy to use and molly-coddling. It is a difficult balance to get it seems!
Your car has a manual that describes maintenance. It doesn't have a button next to the radio that ejects the engine.
This is not a case of "dumbing down everything", the ability to remove javascript is still there, what is not there is one (of formerly 3) often inadvertently used method for it.
> The manual for my car mentions things that must be done for maintenance.
Disabling javascript is not maintenance, it's a significant structural change in the browser's abilities, like removing the car's suspension. And it makes no sense to put that as a switch on the car's dash.
And in order to do something equally complex in Mozilla you grab the help, open about:config and get to work.
Your car doesn't put complex details on the dashboard, and neither should Mozilla.
If you want to continue that, you could consider the manual to be about:config. No one is stopping you from reading the manual or going to about:config, but it's not required.