I think what they intend to say is that if forgiveness is a requirement for your own forgiveness from God, then it is works based salvation. (I don't agree with them, want to make that clear), but they intend to mean it not as you say, as a requirement in our walk, but rather as a requirement for our own forgiveness. (To reiterate, I don't agree or care for their doing away with our Lords words that if we don't forgive and show forth to others the forgiveness and mercy that was granted to us, then we will be judged the same way we judged them, i.e., If we refuse to extend mercy and forgiveness, thinking that because of something they did, they don't merit it, then we will be judged the same way for whatever we have done. In the same measure you poured out, it will be given to you.
Abundant mercy and forgiveness was shown to you. If you bury it and refuse to grow this treasure you have been given, it will be taken from you and given to those who grow the kings wealth.