It's not really the worst comment I've seen about games (or even wargames) on Steam...
I think that part of the "problem" is Steam's policy on prices. Games get old very quickly on Steam and masses of Steam users expect huge discounts on older games. Some other games by Matrix/Slitherine, for instance, also got similar hate when they were released on Steam. For example, Gary Grigsby's War in the East and War in the West is a good case in point. They had already been in use for a couple of years (especially War in the East) when they came out on Steam, and their prices were quite high (with small discounts) considering their age (and considering Steam's standards)... Games as old as Shock Force 2 usually get 75%-90% discounts on Steam. That's probably the reason for the hate. Steam really is a minefield for such games, but it's something Matrix/Slitherine guys should be aware of...