Is one excused by reason of ignorance for having committed major Shirk?

Whoever's Islam has been established does not lose it except with certainty, and after the proof has been established against him, and the impediments to declaring him a disbeliever have been removed. So, whoever falls into major shirk out of ignorance, and is someone who can be excused for ignorance (like a new convert to Islam or someone who grew up in a desert environment), then he is not judged to be a disbeliever at that time.