1) Because the entire field of psychology, like that of medicine, is a wholly owned subsidiary of the pharmaceutical industry these days. Nobody in either field wants to cure or heal people any more; it's all "management," meaning they keep you sick but able to function, because a patient cured is a customer lost. That's why so many Americans these days are on antidepressants and other drugs, far more than actually benefit from them -- it's all about sales. Teaching people to deal with their psychological problems, outgrow them, and become self-actualizing human beings is anathema to the current psych field, since it doesn't sell pills and it doesn't keep people dependent.

2) Jung stressed over and over again that the archetypes are objective realities -- even if they're just patterns hardwired into our brains, they can crush us or heal us with equal ease. The idiots who insist that demons aren't real because they're just expressions of the Shadow archetype have no clue what they're messing with; screw up in your dealings with the Shadow archetype and you can end up huddled in a corner, rocking back and forth in a state of complete psychotic collapse. The archetypes are transpersonal, and they're more powerful than anything the conscious mind can use against them, which is why people go crazy sometimes.

Me, I think the archetypes are even more transpersonal than Jung thought; I think they are reflected in, rather than part of, the depths of our minds. But even from a strict Jungian perspective they are nothing to fool around with.