What else can be justified under the name of being called to peace? Taping the mouths of screaming toddlers? Slashing the tires of the loud car in the neighborhood? One can't just rationalize behavior that will leave their life more peaceful, merely because Paul said we are called to it.
Divorce and remarriage is only allowable in the case of fornication (Mt 5:32). If one's spouse is abusive, there's nothing stopping them from leaving - though they won't be able to remarry. The bible is clear that marriage is permanent, with only few exceptions. That's kinda why His disciples were so shocked, and said it was better not to marry:
Mt 19:10 His disciples say unto him, If the case of the man be so with his wife, it is not good to marry.
Legalistic... They're more what you call guidelines, than actual rules? Welcome aboard the Black Pearl, Ms. Turner.
You're right, God doesn't lack compassion. But that hardly means He allows divorce (and remarriage, presumably) in the case of abuse. Civil authority exists for a reason.
Scripture prescribes lashes (De 25:3), and then death (De 17:12) if he/she didn't turn their act around. The death of the abusive spouse, would obviously then free his/her widow(er) to remarry.
Our civil system's failure to abide by God's law, and refusal to execute repeat abusers, does not then justify divorce and remarriage because of the abusers continued existence.
If a verse does not exist on the subject, then we are free to make our own decision. But there are plenty of verses that speak on divorce (and remarriage, presumably), and none of them allow for abusive spouses.
If we're going to start invalidating scripture with our own opinions, why are we even here? We should just call ourselves humanists and be done with it.