Right, I understand that. BUT, if the people getting Fastpass would have gone in the standby line anyways if Fastpass was not available, then that means there are more people in the line, and anyone behind them waits that much longer. In fact, what it really does is allow some more people to get through the standby line faster because the people who got the Fastpass stay out of the line a bit longer since the Fastpass is (usually) for a time later than how long it would take to get through the standby line. No one should truely be _delayed_ due to Fastpass, but there is always the _perception_ of being delayed. If you understand that the Fastpass people would have been in the line in front of you anyways if they didn't get a Fastpass, then you'd realize that you are not really waiting longer because of it.
This gets back to that it shouldn't have _extended_ wait times. If it did, something is seriously wrong.
As for _shortening_ wait times, i'll confess - it shouldn't have shortened them for the people in the standby line, EXCEPT where Fastpass takers don't actually show up. But it does shorten the line itself, but again that is a perception thing.
Soarin' is a horrible example because they simply just didn't give it enough capacity, and there is no pre-FP comparison for it.