I would not call Gwern race-obsessed. That just seems like rude name-calling. Also, I'm not Lasker and I'm not sure what you think I've exaggerated.
The living person who has done the most work on intelligence in rats that I'm aware of is Michael Woodley. I haven't read his latest research on this, but it looks like it suggests there's g in rats: sciencedirect.com/science/articl