It is irritating when people misuse that term. A shadowban is, when your things get banned for everybody except you, so you think it is available, but it actually is not.
Your game is indexed and available for everyone browsing adult content.
The refresher from a major update devlog is dependent on staff approval. This means, that not all devlogs are approved and when staff has other things to do, probably less devlogs get approved. It also means, this will not happen instantly. It is not a judgement of worthyness of being a major update or not - I guess.
Being dependent on approval could also mean, that they might have games on a blacklist that they would not approve. That's what you wanted to ask. If you are blacklisted for major update approvals. I do not know if they do that, but I highly doubt they would. My observations are from limited data, but my impression was, that a lot of followers mean higher approval rate. Think thousands of followers. You will find several threads about that topic with different experiences being told.