Sure, I get the preference. But these people are acting like GrayJay is somehow worse than completely closed-source software that they use every day. It’s obviously not as good as FOSS, but being able to audit the code makes it a lot more useful and safe than your average closed-source software.
If I had said something about ReVanced, which is a FOSS project that only repackages a completely closed-source app (YouTube) then nobody would have said anything negative. But because I mentioned GrayJay instead, I get gatekeeping responses about “proprietary trash”.