Even without venturing into the most radical interpretations of the butterfly effect, I am of the opinion that the butterfly effect is only a measure of our lack of knowledge.
There is, then, a chance that, through thousands upon thousands of simple cause-effect happenings that ripple through centuries, a sneeze can indeed change the outcome of a war fought 1000 years later. Maybe even by preventing the countries who fought in that war of ever existing.

Each one of these happenings could be easily and logically explained as the logical conclusion of a former cause, but, for any time frame longer than a few hours, they become too many and their interactions too complex for the human mind to even comprehend.
This hobby of alternate history attempts the impossible task of attempting to make plausible predictions of what changes in the outcome when certain start conditions are changed. Unfortunately, human life is so incredibly complex that we can never know how many factors should we take into account -their number cannot be infinite, but it may as well be for practical purposes-. We cannot know with certainty, hence we must assume that, save for very short time spans, the outcome of our scenario will be determined by either our narrative needs or random luck. This is only a measure of our ignorance. The butterfly effect is only the acceptation of this: that the factors that influence history are so complex and incontable that, after a point, we may as well consider their evolution as random luck.