That doesn't tell us anything about who is on 4.0.0-5.1.0 and who isn't. I would also argue that GBATemp users are at least somewhat more likely to use ReiNX than Reddit users.
It appears to, yes.
/r/SwitchHacks users are rather anti-atmosphere at this point in time so many updated in response to drama, much like GBATemp users.
Many joke about Rei because Rei has only shown a splash from ReiNX. They forget where Luma3DS came from and so they show disrespect. They don't know what is happening in this thread.
Incident with ReSwitched was handled the day of ktemkin removal announcement and have already continued their progress again at this point in time. Many have signed off Atmosphere and show disrespect to ReSwitched as well.
I feel it is better to simply camp out on your lowest firmware possible and wait to see who appears with a graceful hacking solution. I really like Rei's update patch thingy that prevents fuse burning.