I first thought the range value in the unit info was off, but then, when attacked by a purely ranged unit ( the command squad has range + melee weapon), they were not able to retaliate.
Thus, I think the problem might be that melee attack and reaction are is triggered when the attack with any weapon is possible.
That would also explain the huge anti tank capabilities of the command squad from range( I tried campaign mission 2 with only command squad + heavy bolter support, and was able to clear the whole map by turn 10, vehicle included, without ever attacking with the cheesed transport vehicles). The Lasgun cannot explain the stellar anti vehicle ranged damage of the command squad.
It is also consistent with the display, as the command squad is represented doing 2 attacks when shooting at a target.

If attacked by the command squad from range 2, the skorcha will do huge damages in retaliation.

No retaliation against ranged attack from heavy bolter support from range 2