In my view judicial hardening is simply hiding or confusing the revelation of truth which could otherwise lead to repentance. So God is not said to have caused or inticed anyone...he simply lets them continue down their already self hardened path and makes sure no revelation convinces them to repent prior to His great purpose being served.
Let's look at another analogy. Suppose my 3 year old daughter was told that she is not to take cookies from the cookie jar. In another room, out of sight, I see into the kitchen that my daughter is looking at the cookie jar. She looks around the room to see if anyone is watching. As a parent, I can tell what she is thinking...she is about to steal a cookie and she knows she isn't supposed to.
Now, as a parent I could step into the room so that she sees me prior to her committing this sin. Upon seeing me she would forego her evil plot and give up the idea of getting the cookie...at least until the next time she was alone. However, suppose I decide to not step into the room. I remain out of sight to allow her to be tempted and then pouce into action to catch her with her hand in the cookie jar.
Now, by not stepping in at the moment I saw she was being tempted did I cause the temptation? No. I allowed it to continue, but I didn't cause it. I could have ended it my simply showing myself, but I didn't. This is like hardening. By simply hiding the truth (i.e. that I was present and watching) I allowed my daughter to sin. Am I in any way culpable for that sin? No. I merely allowed it though I could have stopped it.
Could God have stepped into the 1st century and clearly shown Himself in Christ to make all the Jews of that time believe Him? Of course. He could have done a "Damascus road experience" with all the Jews if He wanted to. He didn't. Instead we see Christ telling his disciples to keep things quite until the right time. We see him hiding the truth in parables. WHY? If men are born deaf, blind and dumb to the truth why would he need to do this??? He did it because he didn't want them to come to repentance YET! He had a bigger redemtive purpose to accomplish through them first.
KEY POINT: Don't allow the context of that judicial hardening of the Jews cloud your view of men's inherent nature. Men are very much capable of hearing, seeing and repenting when confronted by the powerful gospel truth if they have not been judicially blinded to that truth.