It has been mentioned before, but this thread is a good place to comment again:
I (and others) have personally thought for a long time that this was evidence of the long-held antagonism between Knorr/Franz and Rutherford. It is entirely possible that Knorr and Franz wanted to minimize the burial place of Rutherford specifically to avoid it becoming a shrine. After all, post-era the death of Russell, a wide fraction emerged in the society and Knorr the businessman was not about to have this repeated. Russell himself had a sort of burial monument erected (the pyramid) by his grave, and probably they did not want a repeat. Note that if a respectable gravesite was desired, they did not exactly have to put up the Crypt at Beth-Sarim; the Society could have put it in a suitable legal cemetary if they wanted.
Along the same lines - they did not waste much time in getting rid of Beth Sarim and the other property, as well as the two famous Cadillacs.
Equally interesting is the treatment of the burial service - absolutely secretive, even if it actually took place.
Apparantly, Rutherfords own living family (and even the mistresses) had nothing to do with it.