What is Modern and Abstract Art All About?

Many people believe "modern" and abstract art are just crap and that it is made by artists who simply can't paint.
"I don't know how to paint, so I'll paint modern".

No. At least not with real "modern" (actually it is the way modern and post-modern art is popularly called) art.

Sure, there are many so-called artists out there, both amateur and professional, doing so.
Many sell their crap for millions, calling it art. The ignorant public either buy it believing it is big deal, or it is so popular that they worth millions in the art market, so people invest on it.

Everyone has ever asked "what does all those blotches of paint mean at all?"

Contrary to popular belief, art is not at all about representing reality the most realistic way possible. Actually it has rarely ever been. For many centuries, realism was the rule in Western art, but even so it was in such a way as to improve reality or represent it in a simbolycal way that looked real. It is about expressing ideas and emotions in a pictorial way.

Classical and Neoclassical art, for example, used "perfect" proportions in ways that were possible in reality. Portraits would be made not by simply reproducing the likeness as it is, but with "improved" proportions, like a photoshopped picture.

Impressionistic art would sacrifice form to emphasize color and the effects of light. The subjects would be blurry, and all attention was given to color.

Modern art was about expression beyond what could be seen in reality. The artist used line, color and shape to convey what he wanted do communicate, doing away with the real likeness of the subjects.
Abstract art did away with any real subject, just concentrating in color, shape and line.
It usually does not represent anything, just a concept.

The value of such an artwork is in the complexity or profundity of the concept, the techniques and materials used, as well as the impact it has on the viewer.
No wonder it is most of the time beyond the major public understanding, as it is very intelectualized. Most of what is sold as abstract art is actually scam, fashionable "artists" that skyrocket in the art market for their "originality", but are soon forgotten, as they contributed with nothing of real value.