This one symptom of disbelief. You have no insight to justice. You lose it all. It's the believers who the oppressors have united against for no crime, and are defending themselves and holding on dear life while sanctions and stakes are risen.
This is proof that disbelief in God and Mohammad (s) makes you evil. The injustice disbelieving people support is proof that the good people are with Mohammad (s).
I've witnessed few non-Muslims with good sense of justice. Very little have it.
There is a serious problem with your reasoning -- the existence of people who DO have insight to justice, who are kind and compassionate and loving, and who nevertheless reject God and Muhammad.
Evil is when you are willing to harm others in order to get ahead (or at least, most evil falls under this defintiion). Evil people exist both inside and outside of Islam, as well as good people. Thus being a Muslim is a terrible, unreliable standard for deciding whether a person is evil.
In my experience, you have a few very good people, a few very evil people, and a whole awful lot of mediocre people. Religion does not seem at all to be a factor in where someone falls on the spectrum.