This is discouraging. As minnow, I'm finding there are a lot of strange goings on that steer the rewards of steemit in unintended directions.
Is it bad form to refer to one of my posts in a reply? I did a quick and dirty analysis of the distribution of posts and payouts here: https://steemit.com/life/@bobcastleman/the-plight-of-the-minnow
Part of the issue isn't steemit, as such, but rather that people tend to chase the rewards of any similar system rather than use the system as intended. This gives rise to the things that skew the allocation of rewards - things like bots. Plagiarism is a problem because it is easier than generating original content and the rewards for doing it exceed the penalty. Worse, the rewards for combating plagiarism are insufficient to attract a large enough population of "warriors".
I say go for referring to your own posts as long as they are directly relevant.
There are no rewards for fighting plagiarism. Quite the opposite, in fact.