At first, second, and third glance, this certainly fits the bill of your conclusions being predetermined before you have all the facts. More to the point, it would appear that the meat and potatoes of the process was a big fat giant waste of time. It seems obvious that the actual investigation didn't matter much to Comey.
But here is the reality.
The facts (for the most part) were already known. Not just to Comey and the FBI, but to pretty much most of America. The decision to charge or not to charge was more likely a decision made based on Comey's interpretation of the statues, his consideration of past precedents, and such. It's entirely likely that the investigation itself (to the degree that it would offer Comey with a reason to charge Clinton) was effectively an exercise in futility. Comey had made a decision, and was not swayed away from that decision.
The only real question is if there was any chance that Comey could have been offered information that could have changed his mind. Was he willing to rip up his memos, and start over with a new set of memos telling the country why he was recommending charges?
That seems unlikely.
What we will probably "never" really know for sure is whether or not Comey's predetermined decisions to not charge Hillary were actually based on his interpretation of the law, based on his personal political feelings towards the situation, based on marching orders he was given from above, or based on some combination of these possibilities.
