Are you muslim? In the real world most muslims are not that religious and hardly follow what is taught to perfect precision. They would not be able to answer the difference except in vague terms at best.
Every single muslim, whether devout, practicing, lapsed or whatever, knows whether they are/were Sunni or Shia. They are literally born into it. It determines who is seen as the authority in matters of their faith, the way they pray, the sites they consider holy, the religious days they observe. Even Ramadan starts and ends on different days depending on which you are.
It's such a fundamental thing that I question whether you have any idea about what you're saying here.
It's like if you didn't know a single thing about Mandarin but insisted on making claims about its grammatical rules because you know English grammar.