Except there really weren't studies, and this is why the nutrition "science" was so bad back then. A sibling comment mentioned a study in rabbits and points out the obvious problems with making conclusions based on a herbivore, but the general belief was that since high blood cholesterol was linked with heart disease, eating a lot of cholesterol is bad for you.

When they actually did to the studies, they found that the vast majority of people do not get high blood cholesterol from (reasonable amounts of) dietary cholesterol. There are apparently a small subset of people (like 5% or so) who are particularly sensitive to dietary cholesterol though.

That was why nutrition science in the 80s/90s should be such a cautionary tale. So much of it was bad science, or more charitably there were "reasonable" hypotheses that were presented as government-sponsored "facts" that turned out to be false when they were actually tested.