If the top news stories are personalized to your interests, it is more difficult to game the system.
In particular, consider this scenario: I get a news result from a voting ring, and it ranks high because they all voted. But then I downvote the article because it is not interesting to me, Afterwards, the voting ring's weight is diminished in my personalized news feed. Hence, they cannot artificially rank articles for you,
I would argue that without some personalization, it is impossible to 100% avoid spam. Because if you treat there as being one objective lense, it is hard to discriminate between legitimate overlapping interests and colluders who share their authority.