He's saying it's dangerous as fuck to let anyone determine what is appropriate to say and what is not appropriate to say.
When you're talking about infrastructure fundamental to everyone's life determining what can be communicated you're talking about building 95% of the infrastructure of tyranny in one fell swoop.
Do you think the government or the officers of Alphabet will always be Good people that you agree with? History is rife with examples of awful people taking over once-benevolent powerful institutions.