There are just boundaries you shouldn't overstep. That backstabbing move is attempted murder for a pitiful reason. A malicious motive is a aggravating circumstance in my country and leads to higher punishment sentences. I believe it might be possible for me to rekindle with somebody, who tried to murder me without wanting to murder me, depending on the circumstances. If that person gets badly blackmail by threatening the life of his/her kid or if he is an enemy soldier that tried to shoot me yesterday, but today for some reason we have to fight side by side.
That dude though is a lose canon. I wouldn't trust him anymore, but... the thing about Red Ranger is, that he is directly cut out of a kids show including special effects and batteries! The rules don't apply to him, going so far, that he can even summon a Zoid! The plot demands him to forgive that bastard. But it doesn't necessarily demand it from the girls.
Playing all those kids friendly and educating tropes about over-the-top friendship and naive forgiveness has been funny, but in this case my laughter would stuck in my throat. This is the end of sunshine land. This trespasses into the teenager-friendly morals education land of "Friends, that are no friends."