A past is a very personal concept to a person. A person is not defined by what they have or have not done, a long time ago.
My friends accept me for my past, so I think that it is very hypocritical of me to think any other way.
Most of my friends have what they would consider 'a past' that they are not proud of; to me it is their experience in life- something they have had to undergo to make them the person with which I want to have in my life presently.
It doesn't matter to me what kind of past my friends have had. I Love them for who they are now.