Parallel reconstruct is way easier on drug users than CP viewers. Random interception, dog hit on the package, etc. For CP viewer what are they gonna say? I guess that they hacked the computer. But that would entail that the computer seized was actually hackable. And I don't think the NSA is gonna burn zero days busting people for CP. And in fact the exploit that was used against people going to FH servers was a month old and had already been patched.