The DA drama can basically be boiled down to Jennadelle once being exceptionally popular on DA at around 13, people being inspired by her, and her and her fans throwing a fit over it. Some situations were obvious, but others it would be over something so simple as a crescent moon or a mask or a creature that just happens to glow.
She claims to have left DA because of the drama, the people, and art theft.
On more than one occasion, she's said she doesn't do the white knight army thing, but she still went out of her way to actively name and post people who she felt had styles that were too similar to her own. An infamous Livejournal (it was the "this, this, and this..." entry) posting comes to mind, where she outright linked to artists, and people went and attacked said artists. The irony of that being that in the comments, people were linking her own shit and the stuff it was obviously inspired by, proving once again that she was being a hypocrite.
These days, she is a lot more subtle about how she goes about singling people out for having art that is too similar, in that she will contact them privately and ask for them to stop doing something that is perfectly legal, as opposed to tracing screenshots for money.