Hospital software sucking
Haven't worked in a hospital, but I suspect the underlying reason is that selling software to hospitals involves a long, drawn-out negotiation with lots of different people, which means that companies focusing on hacking the sales process beat companies focusing on technical quality.
A lot of the latest web app/mobile app technology is also full of bugs, because it's new and not safety-critical; bullet-proof, battle-tested software will always be somewhat behind the times in the best of cases. Of course, software can be both old and buggy as heck too (http://thedailywtf.com/articles/A_Case_of_the_MUMPS).