What is the view of Sheikh Ibn Uthaymeen regarding excusing by ignorance in major Shirk, and does he have two opinions, one old and one new, and which of them is supported by the Sharia evidence?

No contradiction or retraction has been found in Sheikh Al-Uthaymeen's statements regarding the excuse of ignorance. The summary of his view is:

1. The default is to excuse by ignorance, whether in matters of belief or action, or in apparent or hidden issues, as ignorance removes sin and renders the person not accountable. 2. Disbelief that expels one from the fold of Islam may be by belief, word, action, or omission. However, applying the description of disbelief to a specific person depends on the establishment of proof and the removal of ignorance. 3. The claim of ignorance is not accepted from everyone. One who neglects learning, is complacent in asking, or is obstinate regarding the truth is not excused, unless it never occurred to him that his action was forbidden and he found no one to alert him. 4. An ignorant person from the original disbelievers is subject to the rulings of disbelief in this world, and his matter is with Allah in the Hereafter and he will be tested. Whereas an ignorant person from those who ascribe to Islam, who fell into disbelief, is subject to the rulings of Islam outwardly, and his matter is with Allah in the Hereafter. 5. Proof is not established except after knowledge, clarification, and understanding. The mere reaching of texts is not sufficient if the person does not comprehend them. 6. Whoever describes those who excuse by ignorance as Murji'ah, his statement is incorrect, because excusing by ignorance is the implication of the general texts of the Qur'an and Sunnah. 7. Whoever slaughters for other than Allah, while being a Muslim and raised in Islamic lands, and did not know that this is Shirk (polytheism), he is excused by his ignorance and is taught. However, if proof is established against him and he does not repent, he is considered a disbeliever and apostate. 8. The excuse of ignorance does not apply to one who neglected seeking the truth and was complacent, unless he did not know that his action was contrary and he had no one to alert him.