Well the first and biggest problem with your method is using Redditors as your sample group, which is like running a study for average body weight at KFC.
"Iron Warriors have normal results, but their community is weirdly huge" means that the statistically proven stereotype is this: Iron Warriors players are redditors. Which tracks.
The median Grey Knights player visits the feet subreddit 0 times a year. Eric from Poorhammer, who visits it 10 times a day is a statistical outlier and should not have been counted.
I remember r/gayspiderbrothel . It was a shitpost meme subreddit. After being banned, it was replaced by r/lesbianinsectbrothel, which was also banned. The current iteration is r/pansexualfleabrothel
Statistically Proven Stereotypes For Every Warhammer 40k faction