I’m pretty sure that at least some theists are sincere
Most people are usually sincere and it remains the case that the most significant influence on most people’s core ideological beliefs are social factors. That’s how people work, for better or worse.
We can carry belief-as-attire slightly further and suggest that the totally sincere and unfaked embarrassment someone might feel about being caught pantsless in public is still governed by social factors. Your belief can functionally be attire without you recognizing it, much in the same way that someone in a suit just seems “well-dressed” even though they’re not better dressed in an objective sense than say, someone in a traditional robe or animal skins.
Most people are usually sincere and it remains the case that the most significant influence on most people’s core ideological beliefs are social factors. That’s how people work, for better or worse.
We can carry belief-as-attire slightly further and suggest that the totally sincere and unfaked embarrassment someone might feel about being caught pantsless in public is still governed by social factors. Your belief can functionally be attire without you recognizing it, much in the same way that someone in a suit just seems “well-dressed” even though they’re not better dressed in an objective sense than say, someone in a traditional robe or animal skins.