Arguably it's not as clear as you make it out to be. If there was confusion during the times of the Imams you can expect there to be confusion now. For most people it boils down to "we're right and you're wrong" and everyone has proof, typically from the Quran and Sunnah, for justification of their beliefs. I find it amusing though the hostility from certain members against myself, Ugly Jinn, Panzerwaffe and others.