With the recent addition of the barriers in the CDC, SDs now have a more than comfortable spot to remain safe from potential CD shootings. With that being said, there’s no reason for the fences to also block bullets the same way barriers do, mainly for the fact that the fences:
A) take up a majority of the frontline,
B) provide way more than enough cover for SDs,
and C) are 90% air.
There is no reason, logical or gameplay wise, for fences to block bullets. Making them able to be shot through would provide a lot more variety for Class-D assaults against guard line. If some people want to argue that balance is the main concern, then allow SD to also shoot through the gate to make it fair. SD have more than enough cover at guard line at the moment, so I think they’ll be fine enough without the fences.