Depends. Some downhills are like roller derby and don't take much more skill than watching a toy roll away, others have tight corners that separate the men from the boys. It's definitely not true that all descents take a lot of skill.

Also, the key word here is skill. Riding your bike up a hill doesn't take much skill. It takes stamina, fitness, and perseverance, but not skill; a descent full of switchbacks doesn't take a lot of cardio fitness, it takes finess. And this forum likes to focus on the ra ra meat-head mentality you find in the weight room at the gym. So technical descents don't get much love here.