Wouldn't they more accurately be described as exploiting the entrepreneurs? After all, the workers don't have to buy the equipment they use, or pay for the space in which they work, or take the risk that all the money they spent in developing the product would be for nothing, if the public doesn't want it. If the company they work for goes bust, they can just get a new job. The entrepreneur is out a lot of money.
Rightly so there is a balance there and a reward for risk undertaken by the entrepreneur. Marx didn't disagree with that, he just expressed labour should be valued at a fair market price not an artificially low manipulated price.
Indeed, and in a pure capitalist society, where
everything is decided on the market, the price of a person's labor would necessarily be valued at a fair market price.