Matthew 6:14-15 (ESV)For if you forgive others their trespasses, your heavenly Father will also forgive you, but if you do not forgive others their trespasses, neither will your Father forgive your trespasses.
Gay people do not need to be forgiven for just being gay any more than straight people need to be forgiven for just being straight. Homosexuality is not in opposition to Christian values. Homophobia and the systemic abuse and oppression of gay, lesbian, bisexual, and trans-identified people is opposed to basic Christian values.
When it comes to sexual orientation, forgiveness is important to the both the gay and straight communities. The level of anger around topics related to homosexuality is harming both straight and gay people. A load of anger can make people bitter and can harm people's health. Through forgiveness people can find true peace and healthy spirituality.
Forgiveness is not amnesia. When we forgive somebody, we do not forget the past. In fact, forgetting the past can be the wrong thing to do. We can learn important life lessons from the times we've been hurt. The gay community should not forget terrible acts that governments, legislators, courts, police, churches and individuals have committed. Forgetting the past could place one at risk of not learning history's lessons. To forgive somebody is to decide not to hurt a person back after the individual hurt you. Forgiveness is not something one only needs to do once. You need to forgive every single time the desire to hurt back returns.