Like Isaac, I get a bit weary of the "all modern art is rubbish" brigade. This is probably not a view that anyone would admit to holding, and I am sure they would have a good case and be able to quote modern artists they respect. It is more a question of tone, the exchange of coterie jokes about dog poop etc, and of an apparent eagerness to denounce something without having taken the trouble to understand it. I find my eyes rolling, entirely of their own accord.
It's not that I don't think there is rubbish around. It is more because I have the personal experience of thinking something to be rubbish and then discovering myself to have missed the point; and because the history of art over the last two hundred years is full of examples of work being denounced as rubbish by the great and the good and then discovered to be wonderful by the next generation of the great and the good. There is a case for a bit of caution and humility, initially at least. Then, when you have felt anything there is to feel and formed a view, by all means go for it and express it forcefully.
I also think that education has its uses. I say this not to reflect on anyone else's views on any artist or subject - I don't know anything about anyone else's education - but rather as a reflection of my own experience. The artists I like I have liked at first glance, but then I have found that studying them greatly enhances my pleasure. This may have nothing to do with universities - my own experience has been that academic fine art courses are a mixed blessing.
I also think there are conversations you can't have without knowing something about the history of the ideas that are in play and that (self-)education (the best kind) is the only way to get that knowledge. People who don't have it sometimes get resentful and lash out. Even on Lula, you sometimes meet the spiritual heirs of Benjamin Jowett, about whom an admirer wrote "I am the master of Balliol College/What I don't know, isn't knowledge".
I would need to see the Gursky on the wall in order to discover whether I like it or not. Minimalist works generally don't come across on a small screen. Late Rothko would be my case in point. I used to think them rubbish, until I spent an hour in a room full of them. I am sure there will be someone here who does think them rubbish - no doubt after careful consideration