By that logic no product regulation could ever exist because it restricts in some way the free expression of any corporation subject to it.

Obviously that's nonsense. Government bodies in the US are permitted to regulate the products traded on the market, at least within reason.

> the only reason the algorithm promotes things is because that person signaled that they were interested in it.

What point do you believe yourself to be making here? The only reason anyone shoots up heroin is because they want to. Or alternatively, someone can want a particular product without appreciating the toxic chemicals it happens to expose him to.