I can understand that a lot of people falsely claim this superior look because they have purchased an expensive lens or due to confirmation bias, and I appreciate the effort to call them out. But I don't believe this is the most scientific way of doing it.Ahh, the placebo effect. That may be a possibility, though there are differences between the f/1.2 and f/1.4 such as the larger physical aperture, better coatings, and much better USM & build quality that make using this lens a pleasure. For scientific side-by-side comparisons, at least the ones I've seen, the photos are very similar, but they don't represent real-world shooting where flare resistance and the ability to get reliable focus lock matter.
Note that I say "a lot of people falsely claim"- I don't think everyone who praises a 50L is capable of appreciating its unique features. You and some of the proponents on this forum might have appreciated it for its worth- but I bet there's a bunch who praise it without even having used the lens (as I said, confirmation bias). There is also a bunch who have used it, but not appreciated the difference first hand.
I agree with you about the 50/1.4 in my experience. I feel the images below f/2.8 are quite bland for my liking and need serious enhancement in PP. f/2.8 and above is equal or inferior to my 24-70II. Therefore, it is on Craigslist and FredMiranda at the moment. And this was my 3rd 50/1.4- the first was on APS-C where it was inferior to my 50/1.8 at any aperture above f/2. The second one has slight front-focusing which wasn't working for me as my 5D didn't have AFMA.
So I think it will take a better photographer than myself to get magical photos with the 50/1.4.