That sentence is a bit of a mind-bender in my opinion. Wow. "Dialectical relation to socialism"? What does THAT mean?
But, yeah if someone says, "for these reasons among others" he or she is saying "for the reasons mentioned and some others not mentioned." Let's take an easy sentence: "This car (think of a brand name) has great handling, breaking ability, speed and reliability, and because of this, it's a great car, for these reasons among others (gas mileage, safety, etc)."