He's talking about long-range units chasing you after you've retreated and getting high damage on you anyway.
Exactly.
Currently OKW and USF get a lot more chances of wiping squads chasing them while retreating than Ost
(LMG can't shot while on the move) or soviets, who doesn't have any kind of long-range.
Nothing more distressing than seeing how you retreat a nearly full health squad facing a obersoldaten spam, just to see them being decimated while the spam chases them at maximum range. Meanwhile your squad crashes and bump into every wall, rock or tree in the map slowing their retreat.
Losing a 70~80% health retreating squad due to bad pathing and long-range weapons, whithout being intercepted or flanked, is not fun and undeserved.
Same applies to support weapons, but even worse. Sometimes is virtually impossible to retreat a HMG. I would like that in the case of retreating support units the weapon carrier was always the last man to die.