The Bible makes it clear that followers of God must correct oppression (Isaiah 1:17). So, it is important the Christian understands what is oppression. One needs to approach this using the Wisdom of God, not fleshly, worldly doctrines and thinking. This should be extremely obvious, but yet many in the modern Church became influenced by the world, owing to a lack of discernment or the fear of people.
The Bible throughout tells people to not oppress the widow and orphan (Zechariah 7:10; Isaiah 1:17). Many people think that this is not relevant today because 'modern law' looks after women and children. While there may be such laws in modern jurisdictions which aim to 'protect' women and children, however, that is not the issue.
There are two reasons why this is not the issue. Firstly, God tells His people to care for the needy as an obligation out of His love. This is a command to His people specifically, so what the unsaved do is not His audience in this verses. Secondly, caring for the needy is that which is from the heart. That which comes from mere written human-made law is not love nor cannot be of love, but a mere set of doctrines and actions - all worthless without love. Human-made law does not love nor can it love because it is of the flesh (Romans 8:7; 1 John 4:8). This explains why for all the laws in the world that have sought to outlaw acts of oppression such as slavery and genocide, none have made the world a "better" place.
Merely because one evil is not embraced or accepted does not make a person or persons righteous. For whosoever shall keep the whole law, and yet offend in one point, he is guilty of all (James 2:10). A person who is opposed to slavery, but yet supports abortion is still just as evil as one who supports both. Embracing one evil, while hating the other is to embrace all evil. The good works of the unrighteous, while comes from embracing, accepting or merely tolerating one sin, is not righteousness, but unrighteousness (Isaiah 64:6). A person who is unrighteous can do no righteousness unless he is first made righteous.