This is pretty much how it works at every school I've ever attended. It ended up driving me towards "hacking" by writing a bunch of scripts to register as fast as possible, taught me some basic networking in the challenges I faced while doing that, and occasionally grabbed me a seat in a class I normally wouldn't have. However, I think a lot of other students in CS were also doing similar, because it would never make sense how stuff could fill as fast as they did. As a result, sometimes I would have to beg to be allowed to take a graduate level course to fill a requirement, just because it had seats. Ended up working out for me, as one of those graduate professors ended up offering me a job in my 2nd to last quarter, but I wouldn't be surprised if such overloaded systems just brutally sabotage people's entire education.