Agree broadly, that it is their platform, their rules etcCensorship/de-platforming. Look, its their website/platform. When you sign up to such things, there is a list of small print. If you agree to abide by their rules, you are good to go. If you do not, they will stop you using their platform. Most websites or systems are the same. There are stiff laws for companies who allow their platforms to be used to incite illegal acts or for posting illegal content. Get with the program- there is no free speech on twitter, it's not a country or state, it's a company who provide their platform for you to use, free of charge, provided you stay within their own little rules.
If you don't like that or can't stay within the limits they require, don't use their service- use someone else's or start your own? It's not rocket science these days.