When you're trapped in an abusive cycle, it's hard enough to escape, but when that is compounded by the community looking for someone to blame, an abused person feels compelled to be perfect in order to make sure that they don't end up the blamed one. In that quest to be perfect they stay longer and make more efforts to fix it than is good for anyone. If all people knew that when they ended a relationship that blame would not result, they would not feel as pressured to try to "work on it" when they're being abused (or otherwise in a harmful situation). If it was never seen as a cruel act to break up with someone, people could have consensual relationships that transitioned smoothly into friendship, instead of working to maintain a relationship that has emotionally ended already until both feel resentful. And people could escape abuse without worry that they will be judged for not loving enough or trying hard enough.
It is imperative that we stop looking to blame someone for the end of a relationship if we want to make it easier for people to escape abuse. With our current value set, the abuser risks losing face if there is a breakup, which means they enact more controlling and damaging behavior to prevent the abused one's escape. If ending relationships was not stigmatized as proof of someone's failure or evilness or 'crazy', it would be easier for people to leave relationships that were harming them.
For people not in abusive relationships, a graduation perspective is still important. In a positive relationship, you probably learned a lot, grew a lot, and made positive memories. Breaking up should be seen as a positive rite of passage in this case; the natural progression of all living things is to end. In happiest cases there could be a party with all friends where the ex-lovers talk about what they learned from the relationship and how they hope to progress in the future. If neither person feels the defensive need to be the innocent one, friends don't have to condemn one and embrace the other, and people can end relationships without fear of losing their community or being pitted against one another.
Appropriate responses to the end of a relationship should not be like death "oh no, what happened?" but like graduation "how do you feel now? What's your next step?"