I thought that would be the explanation.
I just thought that the underlying algorithms would be smart enough to know that by now that there are certain things that I am into, and certain things that I am not. To use a simple example, if I am consistently boosting content with certain tags or themes, and I am blocking certain things with specific tags and themes, then the algorhythms should progressively learn my tastes, as they do on YouTube or Amazon.
(Ok, maybe that is a grossly unfair comparison, given the money behind YT and Amazon, but that the idea I’m trying to illustrate)
Also, sometimes I block a user, and still see there other posts before I refresh the page.
I never had this issue on Tumblr.