The fact that they do not supply a way to find the correct answers might be based on the following information.
Harsh editorial comment next, please be aware.
A lot of people aiming for certification, are aiming just for certification and are not deploying the efforts to really learn the subject. They study the sample exams rather than the subject until they know enough good answers to pass the certification. They do not know much, they cannot do much but they are certified. Then they go on some medium, and read article like 10 JS questions and answers to land a job or 10 interview questions for python. They know nothing except than how to get a job. They cannot do the job but they got the job. Not providing answers to practice exam is one way to weed the field of unskilled certified people.