I have no problem with Bob paying for his share of the expenses. He should give to Alice some of that which he produces until he has paid for half of the building and the equipment. The problem occurs when Alice continues to collect from Bob until after he pays for his fair share. In that case, Alice is exploiting Bob with her ability to prevent him from working at the shop.
Bob made an agreement with Alice that she would pay him 1 BTC per hour for his work. Assume this is occurring in a society such as you envision. Does this seems like impossibly abberent behavior based on the way you think this society would operate? If no, then can you explain how such an agreement is exploitative of its very nature, even in such a society? Otherwise, does it bother you that your ideology cannot withstand an agreement between two individuals that you find unsatisfactory?
Here's the thing, I oppose the state because it is capitalistic. Agorists, anarcho-capitalists, and the like oppose the state because they think it opposes capitalism. That makes no sense to me. The state is profitable because one can use it to better exploit others. In the absence of states, capitalists will compete to create new ones. They do so even in the presence of states by creating corporations, amorphous kingdoms. I will not help a capitalist topple one state so he can subject me to one of his own creation.
Correct me if I'm wrong, but you support private property, just not of land and capital? Why do you oppose the private ownership of capital? Additionally, how do you define capital? It seems to me anything from a hammer to a factory falls in that category. If I'm not using my hammer, can someone else just take it as long as they use it? What about my car, because they can put it to better use than sitting in my driveway?