Also, how far do we go with this reasoning? Stripe and PayPal refuse service so they're supposed to "Go build their own" (it costs billions to create a new service like stripe or PayPal that can compare). AWS shut you down? Build your own data center... (Again, costs millions or billions). What if next Intel or AMD decides to not sell you processors? Go build your own fab and develop your own hardware? What if the silicon miners won't sell you silicon, are you now supposed to go build your own mine?
The issue isn't that companies have a right to do it, it's that there are no viables alternatives to these large duopolies, and that "creating your own" is not an alternative.
What happens if the party in power next decides to attack religious organizations who congregate during that pandemic with the same type of concerted de-platforming? What if it's people who advocate against raising taxes who are next as deemed "morally corrupt"?
It's not hard to imagine this type of anti competitive, semi-concerted effort to de platform a new company being targeted at other things in the future. We need laws to catch up to our modern society and either break up the monopolies or put a lot more protections around the types of discrimination that are illegal, which should include political affiliation (this is law in California for employment discrimination so it's not that far fetched of an idea).