Oh, ok, I get the problem, I was talking way above your grade level. I'll answer in short sentences for you.
The money you earn is your money. You also live in a land of laws with a government. In return for the roads you drive on, the military that protects you, the cops you can call, the fire department that protects you, the department of education that helps keep schools running for the children of the country, and other various government agencies that make it to where we don't live in shacks and crap in buckets while having to boil water before drinking it, you pay taxes to keep those services running. To me, it's the exact same thing as saying that the money I earn is mine, how ever at the end of the month I need to cut a check to my mortgage company if I want to have a place to live. At that point, since I legally am obligated to pay them, it becomes their money. How much of it can you keep? I don't know. It's way too complicated of an answer in all honesty. I think if you make at close to the poverty level you should be able to keep alittle bit more percentage wise then if your bringing in millions, though I am against any tax that I think is so high that it will constrain businesses or people from being able to stay open and pay for the basics. Thankfully, right now, the country has uniformly moderate to low tax rates as compared to the rest of the industrialized world and as compared to our historical tax rates.
Now back to the bigger picture. Regardless of whether you think that the money you earn is yours or the governments or whatever, that makes no logical argument that capital gains taxes should be drastically lower than any other income. It's income either way. I don't understand why you think that capital gains, money that has been made from investing income on investments, and money that has been made from investing money into a new business venture, should be treated any differently. Either way it's money that has been risked in an attempt to bring in more money.
Now please answer that question and leave the whole "Is it my money or the governments money?" bull**** at the door. It has nothing at all to do with why you would treat these two incomes differently.