I, too, am glad you're okay!
Given that it was a rebuild of a vintage bike, your first commute on it and first day locking it at that location my guess is that it was user error and not vandalism that caused the crash. I've locked my bike at public racks at schools and colleges for a really long time and (knock wood) have never encountered vandalism of that type. I did have someone steal a quick release bolt from my bike- fortunately I noticed before I rode off but I think you may be jumping to conclusions.