Not all of them, just the majority.
If everyone can get your models for free then they have no reason or incentive to buy your models. Buyers like to sample models but then they will pay for higher quality models that you link them up to. So if you are selling a car you could have the basic un textured version available for free download and then put the high quality version up for sale. That is a better strategy then what you are adopting at the moment. Putting almost everything out there for free is probably not making you any sales.
