Maybe it is because he has a constitutional right to reasonable bail. Don't misunderstand me; I think he is guilty as hell, but he is still entitled to reasonable bail.
I think the bail should be for a much higher amount and that he should be subject electronic monitoring.
His amount of bail wasn't necessarily inappropriate, what's inappropriate is that he paid nothing up front (a signature bond for 40 felony counts against him). I'd like to see any judge anywhere else in the country give that to you or I should we be accused of the same things. No, we'd be sitting in jail until we came up with the moolah. Like you said, though, if electronic monitoring is good enough for Paris Hilton and Lindsay Lohan, it should at least be good enough for this pervert, Jerry Sandusky. Good grief!!
If you have proven assets that are easy to attach or difficult to get rid of in a hurry, such as a lot of equity in a house, a signature bond is quite common.
Remember, a bond only needs to be sufficient to reasonably assure the accused is going to show up for court dates.