These companies know the results they provide are total garbage, and many hiring managers know it too. But it is convenient for both sides to pretend there is some real science behind this and results actually mean something. For hiring managers it is a convenient way to cover their a**es (it's not my fault a bad one was hired - tests were good, and it's not my fault a good one was passed - tests were bad.).
Army: Blast in Korean DMZ wounds two South Korean soldiers (Reuters)
from the article: Want to see your job evaluation? Israeli employers may not show you