I don’t perceive them as meaty but I think that, like mushrooms, they have a umami thing going on. It’s not meat-flavor, but meat also has umami and I think for many folks there is a strong association of meat and umami-flavor.
This. I don’t think of them as meaty, but they are very satisfying.
I’m curious: what made you try the experiment (with your nurse friend on standby - very smart!) on black beans specifically in the 1st place?
Back before my legume allergies (peas and lentils) kicked in I used to eat them and pinto beans and enjoyed them. When I started having bad reactions of course the doctor I had at the time said “eliminate all legumes!” which I didn’t, because at the time I knew soybeans and chickpeas were still OK. But I did drop the others. But I missed having bean tacos so I wanted to see if I could still eat them. I remembered liking black beans more than pintos so there you go.