But voters don't care about Iran. So Iran policy is dominated by the interests of non-voting/non-democratic power structures like US business interests and geopolitical long-term desires. And on these issues, those power structures show marked agreement. So that's what we do, modulo tactical considerations (e.g. the Obama administration pursued a policy of containment and treaty engagement out of conservatism, where Trump installed a bunch of trigger happy cowboys who want to watch bombs on TV; but both viewed Iran as an enemy to be opposed, and for the same reasons).
So I repeat: to you, if you happen to view Iran policy as extremely important, it must feel like The System is conspiring against you to manipulate public opinion. But it's not. It's operating as designed, and 100% democratically. You are just in a minority, and this is what being in a minority feels like.