The explanation given to Rabbi Kagan for the slanted Bayit Sheni mezuzahs is difficult to accept.  According to J.M O'connor, the symbol of the cross was detested by Christians up until the late third and early fourth century c.e., which means the Jews living in the 2nd Beit Miqdash era would not have put the symbol on their doorposts that early on.

1. Title:
   Yonatan Milevsky Yonatan Milevsky, 

   Date: Apr 11 2011

   Correction: The CHRISTIANS would not have put up that symbol that early on.