Off by default lets everyone choose to turn it on if they're interested. It also might clue in Mozillas devs that if they want people to turn it on, a setting in about:config isn't the only place you should be putting the button.
Off by default is neither removing user choice, nor is it preventing Mozilla from saying they ship with feature X. It is the right way to present it.
Off by default is neither removing user choice, nor is it preventing Mozilla from saying they ship with feature X. It is the right way to present it.