The line that Facebook and Twitter are somehow anti-Trump is psyops.
Both companies are helping the Trump campaign.
Today Twitter has declared that falsely calling Joe Biden a paedophile is not against its rules. That is no exaggeration – that is exactly what the company has said. Personally I hope Biden seeks a “cease and desist” order against both Twitter and Trump, or even actual damages.
It wouldn’t surprise me if Fox News are playing the same kind of game, although I am less sure about them. (Paul Ryan is on the board of Fox.)