Earlier quoted context omitted.
Isn't it more likely that the author chose Facebook, Google, and Twitter not because they're left-leaning, but because their traffic is vastly more significant than The Federalist? The three are all top-50 sites globally. The Federalist doesn't even make it into the top 10k. It's pretty rational to focus more on the sites that have the most traffic when discussing bias, isn't it?
> It's pretty rational to focus more on the sites that have the most traffic when discussing bias, isn't it? I feel that if a person is making an argument from principle, then that principle should apply everywhere and not just where politically convenient to them.
> ... although it can be leveraged against big tech companies that are biased in favor of liberals, this line of argument also has implications that conservatives may less readily welcome. For instance, it means that how rich people use their money to promote their ideas may also be a problem, insofar as it distorts the marketplace of ideas.
The principle he's arguing is that when an organization that has a de facto monopoly on a type of information stream (search, microblogging, and social circle media) uses that monopoly to favor one political viewpoint, that is harmful to society because it "distorts the marketplace of ideas" by preventing equal access to said marketplace.
The Federalist is not in this position. For every conservative magazine like The Federalist, there's a liberal one like Mother Jones. This is the "marketplace of ideas" that the author refers to in action, not a distortion of it. So the author is, in fact, arguing from principle, just not the principle you're using.