Because you’re assuming facts not in evidence. I don’t think they are accused of covering up child sex abuse. They were accused of re-assigning priests that had had allegations made against them.
Which in my State would be a crime if they didn't immediately report those allegations to the proper authorities.
The standard here I believe is 'reasonable suspicion' that children are being abused. No one in my State is exempt from this law. Period.
If in fact they aided or abetted in any way those who abused children they need to be prosecuted and harshly. The Catholic Church does itself no favors by 'transferring' them anywhere but into the hands of law enforcement.