Do CS degrees avoid game design so CS majors don't lose interest in CS?

Why should CS teach game design? It is really orthogonal to computer science. And in some parts even to software engineering. CS can be useful for game design, but I doubt there is too much to gain other way around.

Game design and programming is a common elective at many cs programs. I had it as an option years ago and years ago.

Computer Science is about computing theory, algorithms and such, not practical software engineering. You can actually learn computer science without programming.

Game Design should probably be an art school discipline.

If CS courses are supposed to teach students how to do Software Engineering, maybe they should be renamed to be SE courses.

Game design is taught at many schools, though often not a lot of courses (maybe 1 or 2). But if you broaden your scope, the things that go into video games (graphics, modeling like goes into a physics engine, etc.) are taught at many more schools with greater opportunity to dive deeper into the topics.

What makes you think they avoid it?

When I was in uni CS majors could take multiple gamedev classes but they were electives

No, but it would simply be off-putting to majority of the students and they dont need it for anything. There are game focused programs available for those who want to go into game development. They are not mandatory in general CS.

Game design has nothing to do with CS. But students can learn it on their own.

BTW my No.1 pet peeve about universities is they force you to take many irrelevant courses which you can simply look up by yourselves if you so wish.

I went through school specializing in game development. Here are some thoughts:

Game development is all about project management, including managing external teams. The CS is just one part that goes into the whole business. You instead will be working with artists and their tools, from exporting 3D models to playing sound correctly. Getting everybody working productively is Project Management 101. As a corollary, having students make a very simple game (like Frogger or Space Invaders) with multiple people, including non-technical people, is great practice for real-world development while not exploding in scope.

"Game Design" is notoriously vague, but college is a unique place where you can get all the building blocks. You really want to have some experience with music, art, philosophy, theater, creative writing, project/business management, and much more. The broader your experience the more it serves your foundation. College is also a great place to meet many different people (artists, business, theater, music, etc) that can contribute and bounce ideas. You will learn about managing people!

Game development is more Art than Computer Science. Yes it is a simulation that is programmed on a computer, but outside low level game engine development you will be working on much more fuzzy concepts like artwork and "fun" far more than the CS heavy parts. Because it takes so many different experiences combined together, it's hard to make a specific elective or specific major. I do think other majors, like Film and Theater, are a good prototype of what a Game Development major might look like because they too have to combine many different technical specialties into a production.

tl;dr: Game development isn't a single major, but a whole bunch of majors in a trench coat.