I'm asking you what the misinformation is. Is this harder to investigate because the software is closed source? In my mind undoubtedly yes. I know it was harder for ME to investigate because it wasn't open source - no open issue trackers, SCM repository, whatever.
So please tell me why what I said was misinformation - I'm really curious.
Firefox can't fix all the broken sites in the world, but they do investigate issues reported to https://webcompat.com
You can help by reporting sites that don't work for you.