I don't know what you're quoting, but I wish it were the case that something affecting a million people granted each affected individual about a one-millionth share in the decision. I don't think that would always yield good outcomes, but at least it would be democratic. Structures that enable that are what we should be building.
That is why the writer specified "on average", which clearly remains true, at least in the case that the decisionmaker is part of the affected group. The optimistic part is in assuming that latter.
With our level of technology I don't see why we couldn't have that kind of decision directly put into the hands of individuals rather than leave it to "representatives" or worse yet corporations that aren't even required to ask. Maybe I'm not thinking through the difficulties well enough, be what we have with elected representatives campaigning on one set of ideals and then voting the complete opposite way is unacceptable. At least, that should be grounds for imprisonment. Maybe that would be sufficient to get the representative voting system working well enough.