Perhaps I pushed this against him a bit too hard

That's a normal thing, I'm pretty sure that most of us would react in the same way, It's also good that you brought it up, dragon is now much more careful on what he posts so the chances of him posting anything plagiarized in the future just got even lower!

Steemit is one big wallet we all share and if people are spending it on plagiarized content, I feel the need to do something about it.

Exactly, but what people don't realize the supply of steem isn't unlimited, so someone could be taking "your piece of the pie" for nothing, compared to your work, etc...
Also a private note: I'm glad that you got involved in the abuse channel, any help is appreciated, especially from persons who know the right tools & ticks how to spot plagiarism and find it's source. :)