Officials were already aware of the range of possible opinions. The distribution of those opinions among the general public is informative, and bots were used to intentionally distort reality.
In fact, if an agency said "we picked rule A because that is what the most people wanted," that would probably be an error that could warrant reversal of the rule in court. The whole point of agencies is that they're experts insulated from the political process. Their job is to analyze the law and the data to reach a reasoned conclusion (e.g. by conducting a cost-benefit analysis). Courts will reverse an agency if they engage in fallacious or erroneous reasoning. Deciding that an option is better because it is more popular would be such an error.
That's interesting. So does "we got a lot of comments from people noting how they've experienced what looks like monopolistic behavior in isolated instances that might inform whether can can expect this behavior to increase/decrease if we rule for/against the action?" count as or towards a policy argument? Legal arguments I can see being fairly specific, but policy (to my mind at least) is much more open to interpretation. Or is there some specific legal definition of policy argument they must adhere to here?