Why do people say the past doesn't matter but it actually always dictates compatibility?

Anonymous
When you meet someone for the first time, you hardly know about them and the past always shapes the person in front of you now.
Both can have a promiscuous stage. Sleeping around isn't the problem, the problem is both men and women want someone who didn't after their fun time is over. But actually, they are compatible with each other and they should date each other. People with no promiscuous past will judge and consider the past as problematic, whereas people with a bad past will see the clean past of other people as attractive.
So the past plays a role...
Why do people say the past doesn't matter but it actually always dictates compatibility?
2 Opinion