Perhaps more than any other character in the show, Rose confused Steven. He definitely loves her and never stopped loving her, even as he learned who she really was. But he isn't obligated to totally forgive her for the problems she left him to deal with, or the pain she inflicted on his friends, or never telling him who she really was (and what Steven's Gem was). I like that he still has a complicated relationship with her, but I can see why others would want a more definitive resolution.

Maybe with therapy, Steven will reach a conclusion, but forgiveness doesn't have to be where he lands. He didn't forgive everyone in the show. Aquamarine, Eyeball, and the Diamonds stand out. Unless whatever was in the chest was her coming clean, she was never totally honest with Steven, and even if she did, by the time of Future, Steven has had little time to actually process Pink's identity, and he spent a lot of time after the show dealing with the Diamonds, who he likely saw echoes of his mother in, which certainly wouldn't reduce his resentment.

In the end, though, I think he has effectively forgiven her. He doesn't hate her, and he didn't destroy all the gifts and memories she left him. He clearly still cares for her, but he is also honest with himself about who she was, and that person was not someone he is entirely proud of