I'm not Nintendo supporter and play Switch games on emulators. But one justification is, that this is current generation system. And while the developers are not responsible for, this enables easy piracy, and basically each first party game got leaked early and was playable before or shortly after launch. So lot of these people connect the wrong dots and say that the emulator "supports" piracy, which is not true, but depending on the view could be interpreted by some haters.

The Ryujinx isn't illegal and I am pro emulation (I have terabytes of Roms for all kind of systems) and Open Source. The above statement is not MY justification, but what I think is what most Nintendo supporters will say. I talk about this subject with my bro, watch YouTube videos and read forum comments and that is what I get from them.