But the problem isn't that new people join classes. The problem is experienced programmers being in the same class as beginners.
I could often just do the assignments myself and skip the rest of the course. The real problem was when I was forced to partner up with someone new.
I think the problem is deeper than that, though. Computer science is a challenging field and programming is a discipline that benefits from a large amount of experience. Universities try to sell their CS programs as accessible to beginners yet tend to be very quiet about the extremely high dropout rates.
Look at it this way. How well would I do if I enrolled in a fine arts program? I would essentially be a total beginner at drawing and painting. My classmates would include people who have been drawing and painting more-or-less nonstop since they were young children. Is it reasonable for me to expect the same level of career success as these born artists?
There may be a lot of jobs out there for people with basic programming skills, just as there may be jobs doing mundane art and design. But I think it's a bit ridiculous for a total beginner to go into an exceptionally rigorous, programming-heavy, academic CS program and expect to do well. The fact that universities try to sell people on this is disappointing, to say the least.
The problem is that people learning programming for the first time, who don't have a passion for it, can find themselves in a class with those who do. I have witnessed, first hand, people who were beginners getting left in the dust by their classmates on a group project and ultimately dropping out of CS/SE entirely.