Politics isn't Newton's Third Law of Motion. Prior to Musk's takeover, there absolutely and unequivocally was no "equal but opposite" deliberately biased system in place like there is now.

This is a classic playbook in U.S. politics. Conservative media gins up a conspiracy theory (e.g., Hollywood is biased, universities are biased, mainstream media is biased, social media is biased, etc. etc.) and then they use these imaginary foes as justification for actual retribution. There was no purposeful and systematic bias at Twitter under Jack Dorsey (himself, a pretty conservative character, having backed Tulsi Gabbard and RFK Jr in the past election, both of whom both now work in the Trump administration).