There are a couple of reasons why I no longer venture into Open:
(1) The implied threat, often quoted by the more vocal PvP/Open supporters: If you play in Open you automatically consent to PvP. Umm no I didn't, just because Player A feels that way it doesn't mean I have to see it that way. And if you are interdicted, and manage to evade by waking out, your now apparently stand a chance to be put on a KoS list for not doing the 'correct' thing and dying. I will not be player content for some 12 yo (age is the mentality, not the actual).
(2) This one was a little more cerebral I guess. A while ago I was reading a thread in the PvP sub-forum where a Commander in a T7 complained that he was killed by a wing of large ships (Cutters from memory). And the responses from some of the PvP were rather strange. Their main thrust was it was the Trader's fault for flying a T7, and if he wanted to continue to play in open he either had to sell the T7 and buy a 'real' combat ship or get rid of all those silly cargo racks and module tank his trader. When the Commander very politely replied asking how he was suppose to trade if he wasn't carrying cargo the was laughed at and naturally told to 'Git Gud'. The whole conversation annoyed me, here were a bunch of supposedly mature, experienced players telling someone that if you want to play in Open, especially around the Bubble, forego any thought of doing anything except combat or at least build your fleet for combat. So much for everyone being able to play the game their way.
Look I have nothing against Open, just some of the people that inhabit it. If I could be in Open and know that whilst I have a chance of conflict with a Commander I also have a chance of avoiding it, I would. But it seems this small minority of Open Players think it is a free for all and anyone who doesn't abide by their rules suffers. Just remember that a growing number of PvP'ers consider even a low wake out of a conflict akin to combat logging now, that really shows their lack of maturity in my opinion.