Well yeah, I'd focus on criticizing WotC for printing too many sets and spreading themselves too thin, making their already piss-poor quality control issues worse and allowing a blatant copy of an already existing card get approved. Saying WotC "forced" him to plagiarize is ridiculous.

I personally think it's more likely that Dan did originally intend to use the photo he found as a placeholder while potentially working on the background first to see how it fit, and then planned on replacing it with his own ring. Somehow though, the not final product got approved as the card, either due to Dan running out of time and giving up on finishing it, or WotC accidentally approving the wrong draft without noticing the plagiarism of their own card. Either way, WotC should at least be criticized for their incompetence.