No, your case is rubbish. The murderer can have any reason he can dream of to murder you and owes you not so much as an evil laugh. Combat logging to avoid him murdering you is cheating. Simple as that.
I've played this game primarily as a trader, smuggler and explorer, and have only recently (since 2.1 dropped) gotten into combat. Up until about 4 weeks ago I had never participated in a CG and my experience with PvP was limited to being ganked a couple times. So, Joe Everyman I guess in terms of my career choices. I've always played in Open, though. My opinion in this point in time is that in the great scheme of things the combat logger falls several rungs below the seal clubber, mobius invader, noob ganker, Jameson Memorial kamikaze camper. If a player clicks "Open" he/she has agreed to abide by the rules of the game, and as much as some of you guys want to act like that means nothing
it is indeed cheating, and if it could be proven I would support a very harsh penalty...such as being forced to play Open only for something like a year, and possibly have your rank stripped and busted back to Mostly Harmless