Common people with nobody parents routinely wind up as Presidents, Senators, Representatives, and SC Justices.

I think "routinely" is overstating it. These days, "infrequently" is probably more accurate. US politics is very much of the monied, for the monied. Without a huge warchest, barring odd circumstances[1], you've got little chance of making it through the various filters.

[1] e.g an extremely unpopular incumbent against a popular challenger with excellent ground game.

Let's look at Presidents:

Obama - commoner

Clinton - commoner

Reagan - commoner

Carter - commoner

Ford - commoner

Nixon - commoner

Truman - commoner

Sounds like routinely to me.

> politics is very much of the monied, for the monied

This is somewhat true of course (though Obama is a notable recent exception).

Indeed it's pretty true in most countries and systems of government (though my closest experience is here in Australia, where all our prime ministers going back almost 40 years, and most others in our ~120 year history, have come from modest origins).

But the topic at hand is freedom of speech/expression.

Whose interests are likely to be served, ultimately, by constraints on speech/expression?

Those already holding power, or those seeking to reform/subvert the system?