Your entire argument that scale doesn't matter rests on the notion that legitimacy needs to be signalled at all to fool people. It doesn't. It just needs to appeal to people's biases, create social chaos through word of mouth. Also, all you need to get posted on the NY times "account" is to fool some journalists. Scale can help there too by creating so much misinformation it becomes hard to find real information.

Scale definitely matters when that's what you're doing. In fact I challenge you to find any physical or social phenomenon where scale doesn't matter.