These companies are not "discriminating" against any particular political view. Calls for political violence and extremism/terrorism have and continue to be moderated on these platforms from both sides.
It is unfortunate that you don't understand the distinction between inciting violence via either direct calls for such or indirectly by repeating the same unfounded lies of "a stolen election" VS political speech/civil rights, which have not been abrogated (there are plenty of conservative commentators on Twitter, some of whom I follow).
As for my background, I am an immigrant from a post-communist Eastern European country, live in the US in the South and finished with political science and journalism degrees. Can assure you my appreciation of civil rights is intact.
As a general rule, even when situations like this occur, I lean on the side of caution, so I understand the slippery slope argument you're making. There will continue to be a national discussion about what the limits are in the still-uncharted world of social media and the limits of expression vs. platform and publisher rights, but your alarmist view is, IMO, over the top.