Nobody is asking you to.

Nevertheless it is a fact that it was Bungie's intent that Humans == Forerunners.

How you feel about it is irrelevant except as a study on how our feelings cloud our judgement on things that should be obvious.

I used to take on these objections, point by point, to show that they were weak and to contrast them with the obvious things in the story that strongly suggested that F==H but, really, there is no point. Read this post. Evil Otto is Dave Candland a Bungie employee.