"Ought" meaning that I think it's highly unlikely that these calculations come out in such a close race that I don't have clear choices despite using low powered analysis. It might, but like, if the mussels thing looks very likely true, that for example would be a big differentiator over certain other products. Also, there is some variation between brain size and food value. If something IS a close call, there are lots of things that almost certainly are not. That's what I mean by "ought"

One person does not have a large effect on market; I suspect that most vegetarians are being unreal with themselves about the impact of their choices. You can point out a lot of these sorts of quirks about deliberate vegetarians (health claims you mentioned), which may be a sign that there is lots of motivated reasoning going on in that group.

I pretty much just want to make choices more consistent with my ethics or morals or whatever, and desire to do that with minimum effort.