I think the point is that if you try to close the distance with grens who are fighting from behind cover, then they will shred you before you get close. And even if you still have a capable force by the time you get near, they can just fall back rather than lose men. There are of course exceptions to this rule.
This is what I was going for yeah. The mistake I see a lot of newer/lower level players make often is that they take unnecessary manpower loss trying to force engagements that don't favor them. With Conscripts they do more damage at close/medium range so you'll see players try to close distance in a manner that negates any benefit you might get from engaging at close range. Generally speaking in a vacuum you never want to charge an equal number of conscripts at grenadiers behind cover. Of course PPSH increases the net gain you get for closing in and Oorah helps but that doesn't mean that Oorahing PPSH Cons straight into battle is always the best decision.