They are supplying the enemy and thumbing their noses at the Fatherland. BE A REBEL
SINK 'EM ALL
Edit your basic.cfg file
as follows so there's no penalty for sinking a neutral vessel.
[RENOWN]
RenownReachGridObjCompleted=0
RenownPatrolGridObjCompleted=0
CompletedPatrol=0
NEUTRAL=1 <= the default is -1 just remove the minus sign
ALLIED=1
AXIS=-10 <= leave the minus sign there unless you want to also sink German ships too (Onkle Karl won't like you if you do)