I'm always suspicious of anyone who flat out defines capitalism as "exploitive". Perhaps it's a matter of definition, an ancap would support the trade of goods and services by voluntary associations. There is no hierarchy inherent in free trade, and no coercion. Anything exploitive isn't true capitalism.

Just as a socialist says the Soviet Union wasn't really socialist, ancaps will say the current system isn't really capitalist. It's just a slapping match.

We could probably agree on one thing: real anarchy has never been tried. No matter how members of a society organize their economy, as long as power is concentrated in governments (or corporations, or in the hands of wealthy individuals) economic conditions always wind up exploitive.