I mean, they always should’ve been spooked. Collecting money while directly facilitating piracy is exactly what got things like LimeWire killed. The Yuzu lawsuit wasn’t a surprise at all. They did a lot to help progress Switch emulation, but stupid things like working on patches for leaked TOTK meant they couldn’t even argue that they were against piracy. Because the TOTK leak was only available via piracy, and they were directly working on hotfixes while collecting payment from their Patreon supporters.
I wouldn't call it directly piracy. Emulators lets you play games on more platforms. I love being able to play SNES games (Super Mario Island, which I already own) on my PC using an xbox controller.
Pretty sure the dev mentioned they were going to release the source code as well, so it won't really be proprietary anymore. Either way I still prefer melonDS but at least there are options