Not in general, and courts would have to decide whether it's a violation in this specific case. The DMA doesn't force Apple to platform apps used primarily for piracy, it just requires that they be able to justify restrictions and keep them as narrow as possible. De-platforming a specific app is about as narrow as it gets.
Also, it's arguable that the DSA (Digital Services Act), which is just as applicable, actually compels Apple to de-platform this app. The DMA is a competition law, and allowing an app whose primary purpose is distribution of infringing content undermines fair competition among legitimate content providers.
