A USPS manager told me on the phone that if you don't insure you packages they will most likley lose or damage your package on purpose! I had 2 packages get damaged within 1 week, when I called to complain this is what they told me.
What,, Ive shipped about 50 to 70 packages in the last year with maybe 10 of them insured and all have arrived. Sounds like you local USPS office needs a call from the Post master general with a comment like that.