Are passenger/cargo ships viable targets?

[Paul Riley]

I have just been tracking a ship for a good hour (real time) and got set up for a submerged attack.I was convinced it was a merchant of some sort,yet as it got nearer I noticed an interesting stripe running across the top of the hull and the bridge looked unique.Double checking the rec manual I realised this was no merchant,this was a passenger/cargo (my first sighting of a passenger ship to be honest) ship.I broke off from the attack,blew ballast,reported the ship,circled the terrified ship like a hungry shark,submerged again then proceeded back to my previous spot in AN 16.I dont really fancy sinking passenger ships carrying innocent civilians.Was this the right thing to do?,would HQ have penalised me in some way for sinking it,or am I just too noble to be a heartless beast of the depths?
I have one torpedo left in my rather humble IIA,have sunk 2 ships already on this (2nd) patrol,and am very eager for a third kill before calling it a day.

Any thoughts on my action here?

Cheers.