Can Google automatically black out certain articles from websites?

Yes is the short answer. There are a few reasons why certain pages might not be indexed by google.

1. There might be an issue with the page for example you are unknowingly adding it to your robots.txt
2. The page might not be included in your site map
3. If there is very little search volume for the keywords on the page, Google might not see it as worth indexing

Go to your Google Search Console (if you have it set up), if you don’t, set it up. Then click URL inspection. Then paste the URL of the page you don’t think is not indexed. Google will then tell you if the page is indexed. If it is not, it will give you a breakdown of why the page has not been indexed – then just make the changes it suggests and resubmit the URL in Search Console.

For more information on this subject see Google’s guidelines here