A venture capitalist needs to turn down people all the time. Sometimes decisions are scientific, most of the times they are not. Sometimes they are made after extensive deliberations, most of the time in the first minutes of meeting you. It can be that they do not like the sector, do not believe in the idea, do not like you, have a bad day, do not believe that you can pull it of, anything.
When you ask them for feedback, most of them will not tell you the real story. But, VCs want to be helpful. So, some of them will give constructive feedback about your business or the presentation. Some feedback is helpful, some less so. When they do suggest that you include 5 more breakdowns in the year 5 revenue forecast, they were nice to you in giving you a suggestion, but I very much doubt that if you had included those numbers in your first presentation, she would have changed her mind.
Filter feedback and try to drill down to the real issue.