Moreover, identifying as something doesn't necessarily take the form of having any specific opinions. E.g. identifying as southern (in the US) may cause you to have certain opinions, but it doesn't consist of having them. Someone who wasn't southern but happened to have the same opinions wouldn't thereby identify as southern.
Granted, I understand that you are more concerned with making sure people keep a certain emotional distance from their opinions, so that they can maintain a level of objectivity, but I'm not sure that that is always feasible, without adopting a certain kind of passivity or relativism.
It's true, people who don't believe in anything don't argue about religion and politics, they fight over fashion and celebrities.
This is an excessive generalization, and a false dichotomy. The people who argue over fashion or celebrity are those who have incorporated it into their identity. Those subjects are distinct from religion in politics by a matter of degree, not category.
A typical person responds very differently to having their religion criticized than they do having their favorite flavor of ice cream criticized, even though objectively speaking they are both just preferences among a wide number of choices. It isn't even necessarily true that they've given more thought to the former than the latter, only that they identify with that preference much more closely--and criticism of it feels that much more like criticism of the individual.
I'm not sure that this is an ethically tenable position: shallowness extolled as a virtue. It's true, people who don't believe in anything don't argue about religion and politics, they fight over fashion and celebrities. I'd prefer people to have strong, well-formed opinions that they are ready to defend, even against me, to people with no opinion at all.