Maybe there isn't a blatant set of acts that is "biased" on tech platforms that you could point to and say "look see, bias!". Perhaps it is just systemic bias and there is structural suppression of certain viewpoints on the aggregate level.
Infact one of the best things the opposition should be doing is promoting other platforms, if high profile political candidates would abandon mainstream platforms and signal boost alternatives (like the new comer Parler) then it would reduce the power of the platforms
No the platforms want the HIGH PROFILE people, then they suppress the supporters of those high profile people, that is how the game is played
That is how the population is influences, they get the High Profile people to speak on the platform, then only allow dissenters to respond that gives the observing public the idea that the majority disagrees triggering a band wagon effect
I mean really imagine that.
If the tech industry wanted to suppress a particular presidential candidate, not only with that candidate have no account on any social platform, but links to their websites or to news articles that sentiment analysis decides are pro that candidate would be blocked by search engines, and videos of that candidate or pro that candidate would be flagged and removed.