He made a step, perhaps a bit too long in a mistaken direction, but understanding didn’t and won’t stop with him. How everyone reacted to his theory was also part of the fault.

These are excellent points and spot on. We're all looking for the silver bullet and elevator pitch, even those of us who know better. "Oh, just stop eating fatty meat, eggs, and salt!" Except it's way more complex than that. To Keys' credit, he also highlighted the importance of weight management/obesity, cardiovascular health, and "regular" exercise. The definition of "regular" of course keeps getting modified.

Too much fat is still bad.

Agreed, although too much of anything is bad. "The toxicity is in the dose." Keys pushed replacing saturated fats with PUFAs, which became a whole different problem with industrial PUFAs becoming the norm. Industrial PUFAs are high in Omega-6 EFA while being low in Omega-3 EFA. Humans don't actually need any digestible carbohydrates to survive, but we very much need fats and protein to live. Nutritional research has merely been negotiating on where the borders are.

But it doesn’t make the harm of cholesterol moot. Or do you now want to ignore the other data yourself?

We worry too much about exogenous cholesterol, when endogenous cholesterol is the real problem. Cholesterol is a lot like that joke about the guy looking for his keys in the middle of the street. "Did you lose your keys around here?" "No, but this is where the light is." Cholesterol, especially back when nutrition policy was being set, was what we could easily measure, and that was a correlation that science pursued. Epidemiological studies are notoriously tricky, sometimes just a step above anecdote. And to discuss these things in any serious detail requires a couple book-feet of text, most of it being contextual qualification.

Regarding the importance of cholesterol as a risk indicator: What's probably closer to the truth is balance of HDL to LDL and cholesterol to HDL, with triglycerides being a case-by-case basis. If I recall correctly >500mg/dL being the absolute level for concern and interventions, with >200mg/dL being considered abnormally high.

I think in the end, we all have to find what works for us at our given point in life. Because no silver bullet and there's no way to discuss these things simply and quickly.