If PG's arguments were true, then a lot of people whose taste seemed to be quite good, were completely wrong about the Impressionists when they first appeared on the scene. Ditto almost every other new art school. So no one prior to that had good taste? You take a time machine to the century prior to Van Gogh's life, and you might not find anyone in Europe who thought his paintings were good if you showed them what they looked like. So no one in Europe had good taste then?

Nonsense. One can have "refined taste", which means that you can detect all the subtleties of a particular kind of art (e.g. modern abstract art, or modern jazz) that I cannot. My taste in other fields is considerably more refined than the person who likes modern jazz and abstract art; perhaps they cannot stand any science fiction, whereas I have strong opinions about which is good and which is not.

The phrase "good taste" implies there is one standard, one dimension on which one can rate art, but clearly there are many different ones, depending on ones tastes.