This is certainly true and sums up trapped emotions, bitter memories that lead to grudges and depression and can negatively affect one's health. Therefore, letting go is sometimes necessary.
However, letting go does not mean forgetting dangers, situations, people and things that mean us harm.
Letting go is not blind passiveness and suffering in silence in fear. It is our divine right to be assertive yet understanding, firm yet kind and respectful according to the situation.
Letting go has to mean awareness of people's good and negative attributes learnt from experience.
Letting go has to mean learning valuable lessons from our own self-inflicted negative input; and self-criticism, which is far from eternal feelings of guilt, can also help us intuitively grow, aware of our own flaws rather than point fingers always.
And this is the universal, Our Creator-given wisdom, equilibrium (balance) we must apply in our general survival.
I love this. It's applicable in so many ways and also just applies to everyday life. It brings a new significance to living in the moment and not fearing the past or crutches that currently stand in your way. I love it