I don't know a gentle, polite way to point out that you've hit every platitude in its most thoughtless, vacuous form:
- You can still disagree with a private company
- We as a society are thoroughly divided on that, and many disagree that issues of rights and morality are decided democratically
- Political speech you disagree with has value
> Would we have wanted social platforms to give a voice to the "American First" movement of the 1930s?
Of course, it's part of democratic debate. Remember America stayed out of World War 2 until Pearl Harbor. Lindbergh's argument from the video you link is completely reasonable.
They may have a right to do so, but given the importance of social media this gives those companies immense power. For right-wing Americans, simply shrugging off blatant targeting like this is politically suicidal. At this point, their only recourse is to use government power to push back, so we shouldn't be surprised if moves like this push red Americans further from libertarianism into more authoritarian views of government. To not do so is untenable.