No, I didn't notice that. I've seen many unmixed blacks with 3b hair, as well as many unmixed whites. I guess many mixed-race and/or Middle Eastern people have 3b hair, but how can anyone really be sure they represent the majority of people with type 3b hair? I don't see how that can be discerned without a census.
3a/3b
Unsure about density
Confused about porosity

Co-wash/condition: Alberto VO5 Moisture Milks

Leave-in: Giovanni Direct Leave-in Conditioner

Styling product: Clairol Herbal Essences Totally Twisted Curl-Boosting Mousse