Most hits isn't a good proxy for content and it suffers the problem of suppressing newer information. Would that they be censoring the newer sites? Sorry, but this is one of those things that REALLY grates me so here we go...
Search is a VERY hard problem and I truly don't think enough people think about it before crying censorship or know enough about the fundamental challenges. There are trillions of sites, new ones every day.
Let us think of an innocent query: "banana". What do you show? Do we want to show nutritional information, wikipedia, recipes using banana, fruit in general? Let's think more, there will be hundreds of thousands of pages returned and you have to, in some programatic fashion, decide what to "trust" for lack of a better word. Billions of people query your engine, you have to define trust some how. So what is trust? What makes a site trustworthy? SSL certificates? Age? There are too many sites for any human to verify them.
Let's say you have that, now let's think about content. This time we looked for "banana bread recipe". Once again, countless results. How do you decide what recipe is most relevant? Do we take regional content (IE I'm making this query from California) into context? How about how many other recipes that site holds? Some sites have ratings for a recipe, how valuable is that? Should we consider how fresh the page is? If we do that what about the older tried and true recipes?
I caution anyone who spits out a quick answer to anything here. The original algorithm you speak of was PageRank and the internet has grown past it.https://en.wikipedia.org/wiki/PageRank
From someone who works/has worked for many of the big tech companies it truly is frightening that the public, many who are very under informed on how programs work or the scale they operate, thinks things are malicious (not saying they sometimes aren't, recommendation engines have a personal place in hell from my POV) when really they just can't grasp what the problem actually is. Every engineer hits that point, usually early in his/her career, where they have the "if we just..." and eventually realize no, we can't "just" and the problem is massive.
Simply put, you're not wrong but you're far from correct. And, FWIW, "apoe4 forum" query in google is the top result. So there is no censorship, Google is distinguishing context between "apoe4" and "apoe4 forum". "apoe4 discussion" is result 2, "apoe4 community" is the top result.