Whether it gives them the 'right' targets is possibly debatable depending on one's point of view, but irrespective of that, a separate open PvE mode WILL result in fewer targets for those PvPers. Even though those targets may well be willing targets, there will still be fewer targets than at present - which will either make them harder to find or all players will concentrate in a more finite area because they have to to get their PvP fix - for them to do otherwise would make having separate PvE and PvP modes fruitless. Which results in either the PvP mode being focused in a small region, or a mere shadow of what open is now (even the PvPers need to PvE at some point in order to progress). Now, as I'm not a fan of non-consensual PvP myself, I don't mind that so much, but I fail to see what further mode separation will achieve other than divide the community even more (ie like solo is now, the open PvE mode would be seen by some as easy mode and perpetuate the 'us and them' attitude many already have).
It's nice that you are concerned that PvPers will have fewer 'targets', but seriously, who goes into playing a game voluntarily as a target? I really don't believe there are many.
As others have said, mode separation, in this case an Open PvE mode would actually simplify things considerably, you either wish to play the game PvP, PvE or Solo, and you will meet other CMDRs in the first two options who share your gameplay preferences, and if you so wish be able to group up and make friends with them.
As Jockey points out, not everybody comes on the forums, not everybody knows about Mobius, not everybody realizes they can be shot and destroyed for no reason, so an official PvE group will probably give them a much more pleasant introduction to playing with others. To suggest such a mode would be a bad thing seems like something only a PvPer who wants to shoot unarmed traders would do, which you are by your own statement not.
Regarding 'easy mode'. Meh, that's just children calling out names and says much more about the person saying it than it does about the people they are accusing.
.
The problem is not that open allows unrestricted PvP. The problem is that the mechanics of the game and consequences for particular crimes aren't in place to drive PvP into more logical situations and locations. That is, one should be able to anticipate and expect the likelihood of PvP with few consequences in anarchic space or a combat zone. Conversely, in policed space, PvP in the form of an unprovoked attack on a clean CMDR should bring with it severe consequences, such as being prohibited from docking at local faction stations, being actively hunted by security forces (the strength of which would scale with the perpetrator's bounty/criminal status), having to retreat to anarchic space to refit etc. As it stands now, every system might as well be anarchic given the pitifully inadequate consequences in place at present, which makes it harder for PvEers than it should be because either it can't be anticipated and won't be prepared for appropriately (eg by switching from a PvE configuration to a more PvP-suitable one), or it happens where it could reasonably be expected (eg a CG) but the lack of consequences are such that there's little to no risk for the PvPers (in particular those PvPers who insist on preying on traders). A separate open PvE mode isn't the answer though - meaningful and appropriately punishing consequences are.
.
In the absence of those consequences though, I'd take a PvP flag before separating out a PvE mode.
Yes, elements of the crime system in the game are somewhat flakey, but the issue here is that FD want the game to have a strong and significant criminal side to it. You only need look at the PvE side of things to see this where missions to smuggle, steal and assassinate are commonplace, often in the majority. Putting in harsh punishments for such activity would be counter to their vision of how the game can be played, so I suspect it's unlikely that there will ever be a truly harsh punishment for killing. After all, the most prized status to get in the game is (arguably) Elite in combat, and you have to blow up an awful lot of ships to achieve that.