Lots of the previous science was bad science that did not account for confounding factors, such as not taking into account that lots of fast food has lots of saturated fats(and made up for a large portion of saturated fat consumption) and adjusting for that. ie the difference between "do sat fats make people unhealthy" and "does eating fast food(which happens to have sat fats) make people unhealthy"
If you want to go down the rabbit hole, there is also no strong evidence showing cholesterol/eggs are bad, and neither is there any evidence showing salt is bad(if you are healthy). Lots of nutrition studies have such laughably silly methodology. Not sure why they were ever taken seriously.
Dietary Cholesterol / Blood Cholesterol - cholesterol restriction has been removed from dietary guidelines in the US, so people have taken that seriously.
Increased saturated fat is pretty well associated with LDL levels, which is associated with cardiovascular disease risk. Not sure that I've ever seen any contrary studies recently - I would be interested if you could link any you are aware of... I guess the questions I have seen are around carb intake and fat intake, but that's kind of a separate issue
Salt is definitely more questionable, but seems like if you are avoiding hyperprocessed foods, you are going to intake less salt, so maybe a non-issue...
https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD...
There seems to be a moderate reduction in cardiovascular events, BUT - there is NO CHANGE in mortality or even cardiac mortality. Also note, these studies may be victim to the saturated-fats-are-fast-food issue.
If saturated fats were actually bad, like smoking is, I think we would see more significant results than "10-15% decrease in events that doesn't even change peoples' overall outcomes".