Huh? The argument here is "free speech is an important principle, and is being eroded online", then "yes but that only applies to the government", then "no, if

Huh? The argument here is "free speech is an important principle, and is being eroded online", then "yes but that only applies to the government", then "no, if the principle is important, it is important whether it is the government or powerful media corporations in control". Saying that the government is free to create a Twitter clone is a non-sequitur. But yes, to answer your question, the US government has no authority to be in the internet platform business, and that's generally regarded as a good thing.