The arts degree glut is pretty simple. They train too many people for too few jobs.
In the case of communications and journalism, there are other issues. What they teach is largely irrelevant to the coming era of journalism. Furthermore, although technology skills are sine qua non, most of the time you spend is in classes, learning from people who can't get jobs in the industry. You have to beg and plead for even a little time with outdated equipment. (My degree was in the late 90s to early 2000s, so things may have changed now -- but can you imagine a worse preparation for the last decade then learning to cut tape on reel-to-reels? In a single week, on a home computer, you could get more experience using audio editing equipment than I did in an entire year.)
If you were truly fascinated by media studies then I'm not going to say it's a waste of time. But in all honesty we just don't need that many academics that study media.
Also, on the journalism side, the news industry is contracting and unionized, so it is highly unlikely you can get a career by traditional routes. Again, the better education would have been to throw up a website or blog in your spare time, or get a camera and start shooting something -- anything. Or offer to work for free at a local TV station right out of college. People who did this got jobs later. I happened to do that kind of thing too, and I could have leveraged it into a real job in that industry, but didn't because programming was more interesting.
Most of those kids enter the program with dreams of working on TV or film or making music videos and such. A smaller number actually want to be journalists.
Mostly, the closest they get to working in communications is doing PR or possibly advertising. Few of them are doing anything related to their degree after five years.