I think a lot of it is how the individual chapter deals with the issue and who the particular alum and rushee are. I was a legacy through my grandmother at Theta (different campus), and was released after the second group of parties. My grandfather was furious, and was not going to give Theta any more money from my grandmother's estate. I knew I was not a good fit with that chapter, so it really didn't bother me; he eventually came around.
I know that we have had older alumnae who have been very upset because they feel that the reasons their legacies have been released for are invalid or unacceptable reasons. They have expressly said things like "if I was good enough, why wasn't she?" They can take it very personally. Some times, chapters just handle it poorly. But most of the time, a legacy just isn't a fit, and as someone else said, you have to realize it's a different time than when you rushed and there are other wonderful chapters out there. It's the same with getting into the same college, etc. These things happen.