As some have said, it IS only a game. As long as one is able to distinguish between the game and Real Life (tm), I don't see any problems.
Of course, one could argue that any game affects the player, even subconsciously. I suppose for some that could lead to a dangerous blurring of the game and RL. (Imagine someone who shaved his head bald, had a tattoo done, and carried around a hamster called Boo

)
But for most us we know what is real and what is not. The average person is able to distinguish between the game & RL. But games allow us to experiment (albeit in an artificial environment crafted according to the designer's visions, whims and fancies, and not completely realistic) things which we could or would never do in RL. Gaming is, at its roots, a form of entertainment, no different from other legitimate pursuits such as watching a movie, reading a book, etc.
Can a pacifist play a 'violent' game? Personally for me it's not a problem (not that I'm an avowed pacifist). The problem behind BG, or a first-person shooter, or any other game, is that violence in some form or other is essential to the completion of the game. You can't act like a pacifist in say, Counterstrike and expect to succeed at the game. The premise that violence is not the only solution is not built into it.
There are the rare ones that allow both violent and non-violent solutions to puzzles, like Planescape: Torment. But even text adventure games sometimes require you to 'kill', like in Zork where you need to kill the cave troll in order to proceed further.
And what if the game is violent, but there is no depiction of persons being killed? I play Starfllet Command, a tactical simulation of space warfare set in the Star Trek Universe. The fighting is between ship to ship. Most of the time, the object is to blow the other guy to space dust. And all that is depicted in the game are objects, not sentient beings - space ships, asteroids, planets, etc. No crew, Klingon, Romulan or otherwise, just Klingon, Romulan ships.
And what difference between violence in a game and violence in a book? Both are artificial constructs. Both attempt to tell a story. Both are fictitious (usually).
So to me, BG is just a game. A good and entertaining game, but still a game.
Just my $0.02. [img]smile.gif[/img]