Are Christians Considered Polytheists?
The principles of Quranic injunctions are logically coherent and consistent in all their applications. The attitude you shared for a Muslim is quite right that whatever is ordained has to be followed, whether one understands the intrinsic wisdom and coherence and consistency or not. The Quran calls the trinity Shrik, but does not call the Christians Mushrik: لَقَدْ كَفَرَ الَّذِينَ قَالُوا إِنَّ اللَّهَ هُوَ الْمَسِيحُ ابْنُ مَرْيَمَ ۖ وَقَالَ الْمَسِيحُ يَا بَنِي إِسْرَائِيلَ اعْبُدُوا اللَّهَ رَبِّي وَرَبَّكُمْ ۖ إِنَّهُ مَن يُشْرِكْ بِاللَّهِ فَقَدْ حَرَّمَ اللَّهُ عَلَيْهِ الْجَنَّةَ وَمَأْوَاهُ النَّارُ ۖ وَمَا لِلظَّالِمِينَ مِنْ أَنصَارٍ Those who said: “God is this Messiah, the son of Mary,” surely have committed disbelief also, [436] even though the Messiah himself had said: “O Israelites! Serve God, Who is my Lord and yours too.” [They should know that] whoever associates partners with God, God has denied him Paradise, and Hell is his abode and for such unjust people there will be no one to help them there. because they did not accept that what they do is shirk, but make interpretations or Taweel for their doctrine, claiming themselves monotheist. This position is different from the blatant shirk of the polytheists who admitted that they were Mushrik. (5: 72) This Taweel not only provide a basis for them of concession in this world but in the hereafter too, that if they are true in their wrong belief and honestly believe in it, they will be forgiven. See verses 5: 116 to the end of the surah. In the world, they enjoy the concession to be married to their woman by the Muslims and their food (Zabiha) is halal for Muslims. Quran allows for these Christians who believed in trinity or other false beliefs.