Amazon cut off Wikileaks when it was asked to do so by a US senator. Apple didn't need anyone to ask them to block an app from their store that sends users a notice whenever a US drone kills someone - it just rejected it as "objectionable and crude". Facebook erased posts critical of the Catholic church by a German talk show host because someone doesn't like what he said, but does not say who it was and for what reason. And Google has never sufficiently corrected its "real name only" policy that either prevents citizen journalists from using the platform altogether or puts them at risk when they do.
Examples that show the Internet giants' double standards: they rely on constitutional freedom of speech guarantees (i.e. the First Amendment) as a basis for their business models but at the same time deprive their users of these freedoms.
This is especially problematic in cases of journalistic content because of the role journalism has in society - as an essential force in allowing public debate and forming public opinion. Constituting, in short, a society's conversation with itself.
At the same time, many publishers have never been shy of using their own publications for their political aims and economic gains. Now some of them are turning into content distribution platforms themselves. So are they living in glass houses, throwing stones?