You can believe in or participate in something without having it form a significant part of your identity. Usually we say something like that is a "preference" or "opinion", but the difference in name is only a an indicator that it is less coupled to our identity than that it is a distinctly different kind of thing.
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.
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.