It's simple really. Those supporting the idea of sola scriptura must be able to present all of their ideas as supported by scripture.
Those who don't, don't. Get it?
Including the unbiblical and contradictory 'Mary was sinless' Catholic Doctrine which is refuted by Romans 3:28 - All have sinned.................
Do infants sin?
LOL! You've obviously never worked in a nursery. Never yet had to teach a child to be bad, plenty of times had to tell them no and teach them to be good and not bite another child or steal another child's toy!