I bet the difference of opinion that people have over Rose saving Finn largely comes down to whether they believe that there was a chance of Finn disabling the gun.

Those who viewed it as a sacrifice with a chance of disabling the weapon probably have issues with Rose. Those that viewed it as a pointless attack with no chance of disabling the weapon are probably okay with Rose, since she prevented a senseless waste of life.

I’m torn on it. I don’t think it’s well communicated that his attack would have no effect, only that it’s a suicide mission.