This internet thingie is something.
Evidently Rudy M Kuchta is an octogenarian, retired high school teacher, and is/was an Allegheny County Democrat Party Committee member.
He likely was in the Army during the Korean War-——an RMK was conscripted from that county in 1951.
I’d guess that he already knew the basics of the film prior to viewing and that this letter was generated now since the film does not seem to be quickly vanishing.