Define good.
Did you ever stop to understand that your good is not everyone's good? In fact your good very well may be someone else's evil. Rather than accomplishing the greater good, you may be accomplisging the greater evil and promoting misery at the same time.
This absolutely nails it. The truth is that good and evil are hardly absolute (bear with me Christian conservatives) but rather everyone has his own opinion. The real truth is that there are many layers of truth underlying - well just about anything. Whether a thing is good or evil depends on your perspective. Dropping atomic bombs on Japan in 1945 can be seen as very evil, if you are on the ground witnessing the aftermath. But they may have been very good, when you calculate the lives saved by terminating the war before ground invasion was necessary.
Likewise, from the perspective of a fetus, or anyone who believes all human life sacred, abortion is evil. This looks like a no brainer - an innocent babe, how could anyone think this is good? Well some people argue that legalized abortion indeed promotes the general good (reduction in crime):
http://freakonomics.com/2005/05/15/abortion-and-crime-who-should-you-believe/So here we see even abortion can be seen as good or evil depending on the observer and the perspective.
This can be applied to just about anything in life. This is why my personal philosophy is that attempts to control the behavior of others by force (government) should be minimized, because no one has the ultimate handle on what is good and what is evil, but the greatest prosperity and happiness is achieved when individuals have maximum freedom to live their lives as they see fit. No, I do not mean anarchy. Part of living your life as you see fit means the right to join groups that have severe constraints on behavior, such as a religion, or a city with ordinances controlling your neighbor's behavior. This is the genius of our Republic; we are free to move about and live with groups of like minded individuals.
And this is why RvW needs to be overturned. The centralized government has no business ordering states to legalize abortion, but neither should they order it to be illegal. The feds should stay completely out of all matters except those specifically mentioned in the Constitution. Almost all matters are better dealt with on local levels because conditions vary widely among different groups of people.
This is where I find fault with progressivism. You are so caught up in yourself that you cannot comprehend that your ideas are not universal.
Conservatives can suffer from the same. But the difference is that conservatives, generally, understand the rule of law. When people disagree what is right and wrong, you go to the law of the land to settle things, and in this country, the law limits the federal government from interfering in most matters. Progressives on the other hand, tend to wish away the rule of law, and undertake machinations to impose their beliefs on everyone else, through a strong central government.
Progressives do seem to have a blind spot when it comes to imagining that they could be wrong. Take climate change for another example. Progressives are so convinced that their opinions are right, despite not comprehending facts about geological periods, planetary motions, etc. (which make clear that global warming - if true - is very unlikely to be caused by man but rather is a natural phenomenon), that they believe it is their divine mission to implement drastic policy controlling everyone's behavior despite dire consequences. They always attempt to impose maximum controls on the maximum number of people through the most broad government forces. The U.S. government is no longer sufficient; they are attempting global control over things like how much carbon we cough out, whether or not we may own guns, whether we may maintain a border on our own country, etc.
To be fair, conservatives too attempt to use the Federal government to control everyone in the country, for example, proposals to declare marriage between a man and a woman. Here again, it is not the role of the feds to promote or deny gay marriage; they should stay completely out of it. Who may use what bathroom? The founders are spinning in their graves that our highest government is even wasting time on this when it needs to be defending our borders and going after terrorists. The biggest and most important role of the Federal government is edged out and downplayed by all this other nonsense that should be squarely decided at State level.
But though conservatives too do this, I find it to be on matters not dangerous to the survival of the nation, an irritant, whereas progressives do it on matters most critical to our survival. The economy, energy, military, national security, individual financial security - these are all destroyed by progressive meddling at the federal level, because progressives have the belief that they alone grasp how the world works - and cannot see how they might be wrong, despite history's evidence. This makes progressives far more dangerous than conservatives.