Your intended argument is now slightly clearer, but much different from your title and your original posts. You should have titled it, "Depth of field in iconic imagery? An analysis in artistic taste." Instead you titled it in potboiler fashion, and I quote:
"Bokeh: The Most Overrated Technique/Look/Quality... An Amateur's Crutch?"
Now I get what you're saying, and I agree with some the revised conclusion on subjective taste (it still could use some work, your point is that historic pieces of art statistically don't get rid of context through blur; I think this is an argument of taste and selected sample size, which is era-limited, and doesn't take into account types of art styles and eras of art, such as impressionism/cubism/modern vs. realism; in essence, you don't incorporate a greater artistic historical context of the images; hence I would argue that these are great examples of more context through deeper focus for realism/fashion/photojournalism, and yet, still acknowledge this is a conversation on taste), but not the exact way it was argued (statistical approach is still argumentium ad populum). I'd be careful on your wording next time. It started out as derogatory, accusatory and blanketing ("crutch for amateurs") when you may have intended it as an honest question. Your intent is not what we see however (we only see your action, your words in this case), hence the very appropriate comment on how we can't "read your mind" in response to your exasperation.
TLDR: Good taste, but not cogent nor valid. We are essentially left with argumentium ad populum applied to a greater generalization (beginning amateur vs professional shouldn't use shallow depth of field) before you revised your point to "this is my opinion." You should have started there.
If you left it at "using excessive blur amount is often a mistake for beginners," I would agree with you. However, you stretched it by saying "blur quality is overrated and a crutch for ...[wait for it] amateurs" a word you are using in a derogatory sense. You, good sir, are also an amateur by definition. You are a lover of the art who doesn't make money off of it professionally. Read Caryolyn Dinshaw's piece, "How Soon Is Now?: Medieval Texts, Amateur Readers, and the Queerness of Time" to get a good sense of the word and the topic "amateurism" (it talks about Tolkien as an amateur author vs a professional historian and linguist).
Edit: Oh, and Liebowitz and McCurry? They're professionals. They get paid so they can spend all of their time perfecting their craft. If you want to get to their level, you will need a job in photojournalism or magazine photography where you can take critiques from older, seasoned veterans who have the taste to help you hone yours. Shooting HONY-style work on your own with no guidance will not get you there. You can hope and wish, but hard work gets you to your dreams, not expectations. If you have unlimited funds, but no connections or opportunities, it's still a hard and unlikely path. To get to their level of work also involves a lot of communication with people, regardless of the stature they currently hold in society. Humility helps with that communication.