Autism. The problem isn't about owning stuff or being a millionaire. The problem is creating monopolies, something that the left used to be mad about. They now think that just by being rich you are a monopoly... except when that rich person is convenient for you.
Bezos and WaPo aren't a monopoly (technically they aren't), but they were acting in a similar way. Media ganged up against alternative projects to destroy them, using the "it's hate speech!" excuse to shut down many different new platforms. In real life, if your company does that, you can get in trouble with the law, depending on your legislation (I know that it can in my country). Twitter being a private company should be subjected to the same scrutiny as any other business trying to destroy competition for their own sake.