Biden doesn't return results on google, which is interesting. But it doesn't seem to be because google doesn't like reddit. It typically returns results even for niche sub-reddits.

"reddit sorcery of the spectacle" works, for example.

However "reddit married red pill" doesn't (works on DDG).

There must be some kind of censoring going on. Maybe Donald Trump and Biden are somehow influenced by elections. But this wouldn't explain the others.