Google Plus's controversial identity policy requires all users to use their "real names". Commentators have pointed to problems with this, including the implausibility of Google being able to determine correctly which names are real and which ones are fake. Other problems include the absurdity of Google's demand for scans of government ID to accomplish this task and the fractal implausibility of Google being able to discern real from fake in all forms of government ID.

Google argues that people behave better when they use their real names. Google also states it is offering an identity service, not a social network, and therefore needs to know who you are and, thirdly, that no one is forcing you to use Google Plus.

However valid the first two points may be, they are eclipsed by the monumental intellectual dishonesty of that last one – no one's holding a gun to your head, so shut up if you don't like it.

Because when Google's chairman, Eric Schmidt, told NPR's Andy Carvin, "G+ is completely optional. No one is forcing you to use it", he implied the only time a service should come under critical scrutiny is when it is mandatory.

This simplistic theory of critical discourse is perfectly incoherent, implying that in a marketplace, the only role "consumers" have is to buy things or not buy things, use things or not use things, and that these decisions should not be informed by vigorous debate and discussion, but only by marketing messages.

After all, no one forces anyone to eat at a restaurant, so why should we review it? No one forces you to see a movie, so why have any informed public discussion about which movie you should see this weekend? No one forces you to take a job, so why rank employers? No one forces you to go to universities, so why should we debate which ones are best and which ones are worst?

The theory of markets goes like this: over time, users of goods and services will figure out which ones suit them best, and they will spread the word, and bad services will be "ranked downward" (to use Schmidt's language) and good services will rise and thrive. There's some good evidence that this theory works (at least sometimes). Not least, there is Google's own market-like mechanisms for ranking pages and advertisers. There are market sceptics, too, but they, too, don't believe that the world improves when people have less critical discourse.

Here's why we need a critical debate about Google's Real Name policy: first, because it embodies a highly controversial theory of human behaviour, that the way to maximise civility is to abolish anonymity – even though everyone knows Muammar Gaddafi's real name (though not how to spell it) and no one knows the name of the kind driver who slows to let you cross the road.

Second, because it embodies an equally controversial theory of identity: that our lives are best lived when we have a single identity that persists in all contexts over time, so your grandparents get the same experience of you that your lover does, your boss sees the same side of you that your toddler does.

Next, because social services exert pressure on non-users – when all your friends join G+, the pressure mounts on you to do the same.

And finally, because the policy Google espouses is likely to exact costs on its users long after they made their "use/don't use" decision, and those consequences are not easy to discern in advance.

This last reason is the most important one. Google suggests that our internet use is a series of fair trades: I'll give you the management of my identity if you give me easy social experiences and easy logins across multiple services.

But for the trade to be fair, the user has to know what she's giving up: has to appreciate the total cost, over time, of irrevocably – because parts of your G+ use are likely immortal in Google's databases – surrendering to Google Real Name Theory of the Everything.

If Schmidt is certain that the trade is a good one, that users will still use the service even after they appreciate the risks, then he should welcome and participate in debate. He should drop the ridiculous "No one is making you join", talk and bring some of Google's legendary intellectual vigour to the discussion.

After all, Google is the company that set the standard for making everything it does "a beta test". By long tradition, the purpose of a beta test is to solicit critical feedback from testers. This is a natural for Google's service-based model, because Google can update its service centrally, without the old-time inconvenience of pushing out bug-fixes to every user.

The first duty of social software is to improve its users' social experience. Facebook's longstanding demand that its users should only have one identity is either a toweringly arrogant willingness to harm people's social experience in service to doctrine; or it is a miniature figleaf covering a huge, throbbing passion for making it easier to sell our identities to advertisers.

Google has adopted the Facebook doctrine at the very moment in which the figleaf slipped, when people all over the world are noticing that remaking ancient patterns of social interaction to conform to advertising-driven dogma exposes you to everything from humiliation at school to torture in the cells of a Middle Eastern despot. There could be no stupider moment for Google to subscribe to the gospel of Zuckerberg, and there is no better time for Google to show us an alternative.