I think this decision is highly unjust (and no, I'm no privateer nor anyhow affiliated with them). Privateers are supposed to disrupt the economy of an enemy, not to fight their military - so targeting Zoners (instead of KNF or Corsairs), which are the powertraders of Disco, supplying each and everyone, is completely legit, as long as you don't expect to dock on Freeports afterwards.
If you want a compromise, restrict the QCPs to shoot down only Zoner in Kusari space, near Kusari stations or lanes in contested space or trading commodities to Kusari or Kusarian allies. If one of the two sides goes ooRP, sanction them accordingly, but do not restrict their RP. Zoners are just as good as targets as Xenos, Corsairs, Outcasts, Nomads, mercenary or trading companies, Dragons, House Militaries and any other faction on this server bar the Angels, which are wearing Neutral IDs.
Scary as it is - I completely agree with Blunt here.