It is definitely a valid argument. "Facebook should allow all content" is a consistent position if ultimately a stupid one. But once they decide to intervene all of the downstream choices are valid to question.
They were always valid to question regardless but that doesn't mean intervention is inherently good (nor bad).
We actively work to prevent anyone with a suspended license from using the road, so does it follow that failing to do the same for convicted rapists is a bad thing?
I don't think "Facebook should allow all content that is within the bounds of the law of the local jurisdiction" is stupid at all. Ideally that's how infrastructure-esque operations should conduct themselves.
That revised standard isn't obviously stupid, just vacuous, in two ways.
One, Facebook is nothing like neutral content infrastructure.
Two, laws come from somewhere. They are rooted in morality, and are always a snapshot of the historic violations bad enough to drive laws. Anybody who bases their behavior purely on the law has no morals, just fear of consequences. And when it's something new in the world, that stance guarantees ongoing harm until the law catches up.
