I think the biggest problem a lot of people are having is how they feel about Bismuth in relation to Rose, and vice versa. Their ideologies clashed in the end and we find out/are reminded that Rose wasn't just an all loving Mother, she was a warrior and a general.

The bigger problem is, they're both right for their own reasons. Rose wanted to save Earth, she wanted to stop the gem empire, but she wouldn't kill anyone to do so, even her own weapon was creates purely to take an enemy out of the fight without killing them.

But the problem is, when you have an ever increasing army coming after you, and the previous soldiers can rise up, you only place yourself under more and more problems, an army that doesn't diminish and won't stop.

Bismuth saw it for what it was, a war. She loved everyone just as much as Rose, but unlike Rose, wasn't going to make her allies fight the same battle twice.

Bismuth sought to end the war through actual destruction, Rose....we really don't know what her end game plan was. She fought for Earth, to save it but without actually killing her enemies... I would bet, from the beginning, she fought for what she felt, to protect the planet she fell in love with even though she and everyone who sided with her was most likely going to be shattered eventually. They've mentioned many times that Rose did what she wanted, and that includes fighting for a cause she had no idea how to win, but that she had to fight for it because it was who she was.

Bismuth and Rose were both right from different perspectives, and neither were close to perfect.