Well, the magistrate's job is to apply precedent, to which I have no idea why you are of the belief that this is not a routine application of 3rd party doctrine. So that's no reason to hold against the magistrate, even if you disagree with the law.
Second, what colorable argument? There is no colorable argument that entitles you to "discover everything everyone types into the Internet" so there's no need to pretend there is for the purpose of this conversation. Feel free to posit one. You didn't, because none exist. Discovery is limited and narrow. Here, what the court is demanding from OpenAI is limited and narrow, unlike the ridiculous scenario you offered.
Second, what colorable argument? There is no colorable argument that entitles you to "discover everything everyone types into the Internet" so there's no need to pretend there is for the purpose of this conversation. Feel free to posit one. You didn't, because none exist. Discovery is limited and narrow. Here, what the court is demanding from OpenAI is limited and narrow, unlike the ridiculous scenario you offered.