A hard rocker can appreciate the power and weight of a beautiful guitar solo that an opera fan would only consider as noise in the same way that the same hard rocker would never stay one minute in front of an operetta.
In addition, someone who « doesn’t understand art » can admire original sunset paintings, which art connoisseurs consider junk food.
The only conclusion that can be drawn from this is that if a certain type of art is available on the market, it is because it is bought by someone who probably also appreciates it.
What is « good » art?
No one can ever come along and say what is the right art for you and what you « should like ». Art, like any culture, depends on your personal taste. Good art for you is what you like, what you like to put on the wall, and what you feel good about having in your environment.
When you talk more generally about good art, you are talking about artists who are able to convey feeling and expression with their art. Art that creates more layers where you discover new subtleties and nuances as you live longer.
This type of art differs from art that is more or less mass-produced to be easy to eat, flattering and beautiful at first glance, but then gives nothing more. It can be compared to pop hits that are easy to digest, good and enjoyable to listen to, but which you don’t listen to for long and forget soon afterwards.
So a purely technically well painted picture does not necessarily have to be good art in the same way that technically well played music is not necessarily good. However, a creative artist should generally have sufficient technical knowledge to be able to express his idea.