People make mistakes, but the good thing is when exposed with truth, they could realize their mistakes and change.
However bad people thrive by making use of others' mistakes... by identifying what bad things that could happen out of others' mistakes, he/she/they could early set their position.
Not only they don't tell people of their mistakes, they also might create distractions from people realizing their mistakes. Such distractions by giving people impressions that they have done other mistakes that might jeopardize their reputiation. So instead of repairing the actual mistake, victims focus on proving that they didn't commit mistakes and that they are reputable people.
These tricks could be even more dangerous, if victims ended up feeling safe / that they are without fault. Victims could adopt a false confidence that their weaknesses are all out of rumours and politics, and that they might not have actually committed a serious mistake. During crucial time, the bad people would use their knowledge of the victim's mistake to really destroy the victim's confidence and reputation.
Be careful. Pray, discover solutions, and win in Love. Eph 6:10-20, pray for our fellow brothers and sisters also so that they could be delivered from evil and win.