Why do some people think that stem are the only usefull degrees (science technology engineering math )?

Because money talks. If you can’t earn from it, doing it is a waste of time.
Sadly, you can’t earn much from arts and humanities, and thus, those are deemed worthless.

It is a mindset of capitalistic, greedy snobs who arrogantly discard everything just because it apparently doesn’t bring money. In order to fill our pockets, we empty our souls and minds. As someone who studies humanities (philology, to be precise) I got this ish from time to time. If it doesn’t have math in it, it’s bland and nonsensical. If it isn’t about technology, weapons, or making shiny new toys, it’s not worth doing it. If it’s not based on hard, black and white logic, it’s “not real science” and it’s “worthless”.
If you can’t earn from it, it’s stupid and a waste of time. If it doesn’t have any practical purpose, it has no purpose at all.

No one cares about arts and culture. It’s sad, really. Culture, in global, is in a massive crisis, and we are the ones that destroy it with such narrow minded attitude. At best, arts are seen as some cheep fun. At worst, artist and people that study humanities are nolifers that were too stupid for math.

People forget that humans are not just homo sapiens, but homo socialis as well. We are animals that live in society. Not everything is 0 and 1. It’s much more. But 0 and 1 = $ nowadays, and that dictates it all.

Let’s look at it through the lens of a guitar. It takes the science, technology, engineering and math elements to determine what goes into the manufacture of a guitar. They can determine the best way to position the internal bracing for optimum support and resonance; they can determine the best species of wood for the various parts of the instrument; which materials to use for the strings. All these things are important. Of no less importance are the knowledge skills and abilities needed to transform the sounds into music.