I think it's extremely hard to reverse engineer passionate defense of an issue by a true believer. For example, if you were body-swapped with the late justice Antonin Scalia, I find it highly unlikely that you would be able to argue as vigorously for the conservative cause if you had lived your life as a liberal Silicon Valley tech geek (they'd also see right through you because you'd be a zombie and clearly not the true Scalia). So that's one thing.

Perhaps in some extreme pathological case you could have a person live their entire lives faking the opposite political ideology. But that just seems like a waste of energy... And if you can fake being for an issue convincingly enough, doesn't that have the same effect as being for the issue anyways? Like, people would catch on if you wrote about being a Bernie Sanders supporter in your bio, but wrote/submitted all articles about how he doesn't have enough foreign policy experience. The only way to fake being a supporter of something is to.. consistently make solid arguments in support of it.

It's hard to fake an IAT.

https://implicit.harvard.edu/implicit/education.html

By not having anything to sell.