I'm afraid you're glasses are a bit too rosy. It's true that while you're still at home you could start your own company. But some people don't get that inspiration until a bit later in life. Once you have a wife and kids, you cannot make a business unless you get funding. So if people who give funding are racist (I have no idea if they are) then minorities have less chance.

So at the very beginning anyone has a chance. But once you have some responsibilities white males still have a lot of opportunity to make their own business and other groups may not.