They are voluntarily choosing to be a publisher. Publishers are responsible for the actions that the users do on their platform.
States are happier with and want more publishers as it's easier to censor, add surveillance and control them than neutral platforms.
The few past times when Cloudfare censored politically was interesting as they quickly made apologies because they want to be seen more as a neutral platform than a service that nation states can control.
It's why modern internet legislation across all parties and across all nations is geared towards changing platforms into publishers.
And it's why the services that we would have seen to be independent and neutral in the past are choosing this new paradigm.