For me, the difference between the Dürer hare and the Rothko Yellow and orange rectangles, is that it is glaringly obvious that the person who drew the hare had a great deal of skill and talent, whereas it is not obvious to me at all that the person who painted the yellow and orange rectangles had such skill or talent. For me, that matters. Which is not to say I don't appreciate some simple art, but when 'simple' art is passed off as great art, let's just say I hae ma doots!
In a similar way, I might think that a wonky, holey square knitted by a six year old is delightful to look at and a real accomplishment because of the effort involved in producing it, but the knitted fence on another thread is art because of the skill, the understanding of the materials and the technique, as well as the effort, is all obvious.
Further, I don't think Emin is trying to say the same thing with her unmade bed, nor Rothko with his rectangles, that Dürer was saying with his hare. On a positive/negative scale, Dürer's work has a high positive score, Emin's a large negative score, and Rothko's (so far; only heard of him yesterday) is somewhere between them.
I realise this is just my opinion. I guess art is in the eye of the beholder, like beauty, but I'm not ashamed to say that I don't like Emin's work, and I don't think she's an artist according to my understanding of the word. Some of her drawings show some skill but not much. Picasso's early drawings, and Dürer's drawings and woodcuts show astonishing skill. I am impressed by the skill of many artists whose paintings/drawings don't particularly appeal to me, so I regard their work as art. So far, I haven't been impressed by anything of Emin's that has come to my attention, though I must admit to having been astonished — at it, rather than by it.
Now I've burbled enough. Drowsy after a morning's garden work and going for a lie down.