The question Is there any book about topic modelling in machine learning for math student? is closed with the reason that it's not about mathematics.
Reading What topics can I ask about here? - Help Center - Mathematics Stack Exchange, I fail to know why. The closest reason I see may be:
Questions seeking personal advice for choosing a course, academic program, career path, etc. Such questions should be directed to those employed by the institution in question, or other qualified individuals who know your specific circumstances.
But it's about books, not courses.
Moreover, I don't see how this question is any different to What is a good book for math students to learn machine learning in depth?, which has 4 answers and stays opened for 6 years.
Can you help me explain why?