The difference lies in their experiences and their environments.
Marian saw the best in humanity in SKK. SKK became her reason for living.
Maxwell saw the worst of humanity in Syuen, Enme and Jien. To the point she lost her life because of they were monsters among humans.
Every characters experience is different and thus their motivations will inevitably be as well. I don't think you can compare then 1:1 and it will be fair