IYou can, of course, start an endless (and pointless) debate about what is a rpg, but why? Its like some other debates about certain words. Like, some things are art, some are not. What some call art, I would call trash. (a lot of so-called modern art to me is awful and not art, but just garbage, for example)
It wont surprise you to find out I'm well versed in that debate as well.
The reason you see a lot of art that you believe is trash is because art has two primary components.
Firstly, art is the production of something that is purely aesthetic - something that is not entirely confined by a functional use. A chest of drawers is not art, but the way a chest of drawers is finished and presented is - the non-functioning parts that surround the functioning parts are the art.
Secondly, art is a means to communicate something, usually an emotion, but can be any of the indescribable feelings humans get struck by, that is otherwise incommunicable. And the extent to which that communication effects people and causes a reaction in them defines how much artistic merit something has.
A fairly boring and mostly utility only chest of drawers of little artistic merit:
A much more interesting chest of drawers with obvious artistic merit beyond basic functionality:
A modern art style chest of drawers which is obviously capable of inspiring all kinds of emotions and greatly transcends the purely functional aspects of the object who's design practically demands comment:
Genuine trash art would be art you wouldn't even feel the need to comment on it's trashiness. The act of being outraged by something to the point where you feel the need to comment on it proves that the trash is not trash, it has inspired comment, unlike the 1,000,000s of art pieces that pass us by and into the actual trash can with barely a raised eyebrow.
Even people of older times considered most art to be trash and landfills are replete with a million and one attempts to draw a normal boring landscape.