- presumably your 'etc' includes premature fin failure BEFORE the rudder input (not by aliens), then?
According to the data in the report, the lug failed AFTER the train of alternating rudder inputs: an audible "bang" which correlated with a change in lateral loadings. It failed at near 2x the limit load and well over the ultimate design load, w.r.t. the aerodynamic studies. It appears that the fin failure was anything but premature as it seems to have hung on well beyond what it was manufactured to withstand...
I don't see much in the report (not that I've read every single word) that would lend itself to a 'premature' scenario. To do that you'd have to regard the data and conclusions as false/incorrect, which takes you into conspiracy theory territory.
If there's anything simple to be gleaned from this accident it must be to leave the rudder alone at high speed (240kts/275mph in this case). An unchecked PIO often ends in disaster.