But it's it ethical for the site owner to block access to random people and companies in the internet to _my_ data? I posted that tweet with the expectation that it's gonna be publicly available. Now the owner of the site is breaking that expectation. I would say that this part is also unethical.
Especially since they're not moderating things or anything.
Agreed. However, it's probably covered by their terms of service.
Same thing with the recent reddit kerfuffle. I'd have much preferred a Usenet 2.0 instead of centralizing global communications in the hands of a handful of private companies with associated user-hostile incentive structures.
Especially since they're not moderating things or anything.