Yes it would dilute the voting pool for everyone, including the offender. Posting accounts for 75% of the reward pool. By more people posting, the reward pool is spread over more articles. Since one is tapped at 10 100% upvotes, unless willing to dilute by adjusting voting weight or using more than 20% daily, he or she is powerless to combat the dilution regardless of how much SP one has. It is the same reason the whales are losing power each time I interval I post in. Too many newer people putting up articles.
The point is the increased number of posts would enhance this blockchain by making it bigger. We would get more organic traffic since the search engines would have more to index. There would be more activity which would get newer people involved.
Plus it would eliminate the possibility that an article like I fictionally wrote about in the post appears in Medium or any other publication.