Why did some scholars not excommunicate Al-Bakri and Al-Subki, even though they permit seeking assistance from other than Allah, and even though interpretation of the Two Testimonies is unacceptable, and Ibn Taymiyyah refuted them?

The interpreter (mu'awwil) is more excusable than the ignorant person because he believes what he is upon to be the truth and defends it. Interpretation (ta'wil) is an excuse in practical or theoretical matters, but there is no room for interpretation in the two declarations of faith (Shahadatayn), the Oneness of Allah, the certainty of the Prophet's message, resurrection, Paradise, and Hell.

Whoever believes in Tawhid (monotheism), the Messenger, and the Last Day, but then disputes about Allah's attributes or permits seeking help from others, relying on doubts and aiming for the truth, then he is ignorant or an interpreter (mu'awwil) and is excused. He is not declared a disbeliever until the proof is established against him and the doubt is removed from him.

Shaykh al-Islam Ibn Taymiyyah holds that later generations who delved into matters of polytheistic seeking of aid (isti'atha shirkiah), despite their ignorance of the effects of the message, are not declared disbelievers on account of this until what the Messenger brought becomes clear to them. He indicates that the people of knowledge and Sunnah do not declare those who differ with them as disbelievers because disbelief (kufr) is a legal ruling, and declaring a specific person a disbeliever is contingent upon the prophetic proof reaching them.

The Muslim who strives (mujtahid) in seeking the truth is excused if he errs, whether in theoretical or practical matters. This is what the Companions and the Imams of Islam followed. So, whoever's Islam is established with certainty, he is not declared a disbeliever until the proof is established against him and the doubt is removed from him.