I liked Silent Running too. It’s been years but if I remember correctly the main character played by Bruce Dern was good old fashioned rebel, not a commie conformist.
He worked (and I did during summers and vacations) with Douglas Trumbull and John Dykstra at Future General Corporation.
We also worked on the first Star Wars movie as well as Andromeda Strain and many other sci-fi movies (special effects), it was loads of fun growing up around it. :)