As you know, I replied to you on this elsewhere, but I'll now reply here for the benefit of other people also.
The chapters in the quran are sorted by length, from shortness to longest, rather in terms of chronological order or in a way optimal for clarity.
The Islamic view is that the more recent (the latest) revelations have the most weight: if they contradict an earlier verse, then the earlier verse is disregarded.
There are suppose to be two distinct phases, the Meccan vs. the Medinan. The Medinan verses are more violent, and call for perpetual war against the non-Muslims. Indeed, the chapter that is believed to have revealed last is exactly that, it's probably the most violent.
So, when Muslims refer to the peaceful chapters, they're either ignorant or being deliberately disingenuous.
The quran after all does permit lying.
Excerpts below from: The Critical Qur'an: Explained from Key Islamic Commentaries and Contemporary Historical Research
Image 1, from the Intro:
Image 2, on Sura 48
Image 3, on Sura 48
Image 4, on Sura 48