All of the things you have mentioned are just difficult aspects of the assessment requirements for the course. So long as the assessment rules and standards formulated by this professor are within the scope of university assessment rules, then it is within his academic discretion to do this. (You do not mention your university or even what country you are in so it is hard to offer a view on the likely state of the assessment rules.) Imposing a requirement to pass a midterm exam in order to be able to sit the final exam is an unusual practice, but it is really not so different from imposing prerequisite requirements between separate courses --- in this case he is effectively splitting his course into two parts, and successful completion of the first half of the course is a prerequisite for sitting the assessment in the second half.
Many academics on this site will regard this kind of harsh assessment structure as bad practice; whilst it is not how I would structure my own assessment, I'm more agnostic about this --- I certainly don't think it is the worseworst thing in the world to have some courses like this impose intermediate "hurdles" which are hard for students to pass. It is desirable to allow some variation in assessment practices to give scope for innovation, so I think it is best not to put professors on too tight a leash. It sounds like this professor is satisfied with his assessment practices, notwithstanding the dissent expressed to him, so I see little value in trying to lobby for change.
Another thing to consider here is that some early courses in degree programs can act as a "filter" to ensure that only high-quality students proceed to the next phase of the program. In programs where early courses are too easy, this often leads to low quality students coming into later courses without the requisite level of knowledge and prowess in the subject. This is extremely frustrating for the lecturers of those later courses, since it is something that makes their own teaching substantially more difficult. As someone who has been in that position, I prefer lecturers of early courses to err on the side of making their courses too hard rather than too easy, so this guy would be welcome to teach courses that feed into mine!
My recommendation would be to accept that this professor has the discretion to set the assessment for his course how he wants (presuming it is within the university rules) and that he has made a decision with knowledge that many students do not like his assessment structure. Concentrate your efforts on studying hard and trying your best to pass the midterm and final exams.