Why do some people find vegetables so repellent when evolutionarily they should find them an attractive and thus tasty food?
Evolution is not that simple. There is no selective pressure for a feature if it does not ultimately in some way benefit reproduction or the offspring. Vegetables are healthy for us now because we live much longer than we used to in an environment not dominated by us, and they contain many nutrients which help to sustain a healthy body beyond, say, 50.

However, if you imagine an average life span of around 30, it becomes clearer why evolution would favour foods high in energy over foods containing high amounts of micronutrients. Over such a time span, the long-term effects of a diet rich in fat and sugar do not develop significantly, but the energy supply is exactly what is needed to sustain bare life to the reproductive age.