The analogy is that if someone made a Main post saying "hey guys, you should wear Vibrams because they're better for you", that could get downvoted because it's not a suitable topic for Main, even though a disproportionate number of people here wear Vibrams.

Part of that is how the post is motivated- if it's cast as an example of "here's how ergonomics can make your life better, and making a one-time investment can pay large dividends," then it might get upvoted whereas it might not if it's a standalone endorsement for shoes.