You seem to believe that in its condemnation of the Christians the Qur'an only refers to the Christians of Arabia of the time of the Holy Prophet. These verses have no relevance to the Christians that had preceded them or to the ones that came afterwards. I want to ask: Isn't every verse of the holy Quran meant for all people at all times? I believe it is. Please comment.
The Holy Qur'an is the narrative of the Prophetic Mission of the last Messenger of God. There is no denying the fact that its message is universal and is meant for all the future generations till the Last Day but certain matters only confine to the present addressees. For example it deals with the maladies of the Jews who were its direct addressees. No doubt it sometimes refers to the Israelites of the past but the very purpose of such reference to bring a point home to the direct addressees among the Jews. When it stats that the polytheists of Arabia are to be executed because of their denial of the Messenger of God despite their being convinced of his veracity it cannot be extended to the polytheist of later time. For they have never been dealt with by the Messenger who could make the message so clear to them that they are not left with any excuse. Similar is the case of references towards the wars fought with the opponents and special guidance for the Prophet to follow while treating a specific matter.