Even if you have followers, if your individual tweets don't engage well, Twitter won't show them to 100% of the people who explicitly follow you, thanks to their algorithms. YouTube is the same way, which is why you see channels telling users to do three clicks to actually follow: subscribe, notifications on, notifications set to "all". They censor you from your own opt-in audience unless your content is clickbaity e…
There's a whole thing around censorship not applying to private platforms, but even if you argue that the word "censorship" applies to a private entity moderating the content it publishes with its own money (like Hacker News: It definitely moderates content), the thing you describe is still not that kind of "censorship."
Showing or not showing your tweets based on Twitter optimizing for engagement and advertising is not like a government deciding that nobody is allowed to criticize the Dear Leader.
It's actually like a grocery store that promises to stock your product for free, but you aren't Coca-Cola, so you get shitty shelf space and positioning, until you either pay up for shelf space, or build enough demand for your product that the store decides it can make more money giving you better positioning.
Twitter also moderates content in a way that has nothing to do with engagement and making them money. But if you give someone free content, you have to accept them deciding how they feel like monetizing that content.
If you don't like it, write a blog.