I feel you are neglecting the possibility that lever ergonomics matters to those folks who are happy with Shimano, but who have very different hands than you do. You are a big guy, what 6'2" or 6"3', and maybe have big hands. I dunno. But supposing that is the case. Now if someone the same amount on the other side of average size has tiny hands, perhaps the Shimano is better for them. Just because someone likes something that you don't doesn't mean they are necessarily indiscriminate. That is one explanation for sure, but not the only one. It makes more sense to me to believe that the Shimano shape is right for lots of people. True that I have never heard anyone complain about the Campy ergonomics, but very, very few Shimano riders have ever experienced Campy like you have. Not too many folks have as much experience on multiple brands and models of gear as you do.

Here is another example. It is the same for bibs vs. standard shorts. Just because some folks complain about how uncomfortable standard shorts are for them, it doesn't mean that others who don't mind shorts have the problem but just can't feel it. In most cases I would say that for them the problem simply doesn't exist. I know that is the case for me. In fact I find that the bibs are the uncomfortable choice. So I can feel a difference; it just swings the other way.