I understand your frustration. I live about a half hour from Shabbona and don't hunt it very often simply because it's difficult to get anyplace good where you won't see 2 or 3 other hunters. Yes, there's a lot of acreage. But probably half of that is open ground (dove and waterfowl fields, CRP etc.), not timber. During gun seasons it's always filled up early simply because it's one of the few, if only, public hunting areas up here open to bowhunters at that time.
If I hunt Shabbona, it's during late season when the temperatures are single digits or lower. The property's not very crowded then, and it's easier find a good spot all to yourself.
Personally, I won't still-hunt small patches of public land up here (Shabbona and Silver Springs come to mind) because it's pretty much impossible to do without messing up other hunters. I understand that I have as much right to be there as they do. But I wouldn't appreciate it if someone knowingly messed up my hunting, so I try to do my best not to interefere with anyone else.