In addition to which, the 40 hp is just way too low. I've seen a few get ZiS sniped with just a normal shot, and any sort of indirect fire can basically just instakill them.
Peter from Relic said that indirect fire is meant to be the counter to snipers. The problem is, as you said, it works only against the german sniper. Also I remember from vCOH how many snipers died to AT guns in general until they finally fix this in some patch. It is however hard to say if snipers die to AT guns in COH2 cuz no one build german sniper and not so many soviets waist time with ZIS and PAK on the other hand gets very quickly decrewed.