This confirms how disingenuous/delusional "free market", "free association" and "free assembly" arguments are in this case. Decisions by entities of this size simply cannot be interpreted under a "free association" lens, except to the same extent that Lockheed-Martin not selling arms to Iran, or, more pertinently, Baidu not serving up photos of the Tiananmen Square protests, can be interpreted under the same lens. You cannot conclude that an act of censorship is not a state or government wielding its power merely because it is done by a private company,
Nominally, Tencent is a privately owned company freely choosing who they provide a platform to [2]. But in reality, they have absolutely no choice but to ban Winnie the Pooh, unless they want a state apparatus to make their lives incredibly difficult from then on.
The same in the US: these are not mom-and-pop stores with immediate agents and agendas exercising their free association rights in accordance with their personal beliefs. These are large tech companies, deeply and inseparably intertwined with public authority and the political parties, lobbying and making political contributions on one side, seeking political approval and avoiding threats of regulatory retaliation on the other. They know full well that if they ban the wrong speech and refuse to ban the "right" speech, they face being regulated out of business. Indeed, seeing this threat, we see them scramble to align with an incoming administration.
You don't have to be an all-in free speech absolutist to see what's wrong with this: we're not talking about people with fringe views having to move to fringe platforms, we're talking about the campaign of the largest (soon-to-be-)opposition party being banned from major platforms en masse, while people with significant credibility regarding authoritarianism [1], who also happen to be on bad terms with said opposition party [2] denounce these acts as "unacceptable acts of censorship".
[1] https://twitter.com/navalny/status/1347969772177264644
[2] https://www.abc.net.au/news/2020-09-05/donald-trump-us-has-n...