Stealing doesn't create capital. It moves it. Your points 3 and 4 also indicate you don't seem to understand the difference between creating capital and moving it.
As for buying and selling stuff for a profit, you may not be producing stuff with your own hands, but you are enabling more production to occur.
Here are a few ways to create capital without producing anything:
1) Buy wholesale, sell retail
2) Buy in area A, sell for more in area B.
3) Buy all of product X, create a monopoly, sell at whatever price you want
4) Buy product X, hold until price goes up (or manipulate the price), sell
5) Steal