Juan Cole dismisses the idea that Romney has effectively killed people by closing down their companies (and relieving them of their health care benefits), but lists ways in which his policies would literally result in more deaths:
Now, all presidents get people killed. They fight wars, authorize covert actions, and pursue wrong-headed policies. It isn’t useful in my view to engage in a Utilitarian argument about which presidents kill more people and which less. These things are hard to quantify, anyway. The real question to my mind is how many people you kill as president out of cynical calculation about your personal interests and perhaps those of your backers. The thing I most object to in Romney is that he is willing to kill people to get elected, even though he knows better. He believes in Obamacare, obviously, but says he will repeal it. He knows the score on climate change, but is going to deliver us into the scalding clutches of Big Oil. He is a walking billboard for the message that religious people aren’t always ethical people. I sometimes wonder, in fact, whether religiosity doesn’t enable unethical behavior, reassuring the believer of his or her goodness and salvation and so damaging their ethics bullcrap meter.
I agree with Juan's thesis here - what seem like relatively small policy decisions actually translate into massive effects on the ground. Romney's policies on health care aren't hugely different from Obama's (and if you compare his policies in Massachusetts a few years back, their almost identical), but they mean the difference between several million Americans getting insured and several million Americans not getting insured. Both men have catered their policies to benefit the insurance industry above all else, but Obama's have far better outcomes.
I do think there is a need to be careful about language though - accusing Romney of being a 'killer' and a 'murderer' are strong terms, and this could be applied to anyone making policy decisions with bad outcomes. I don't think that Romney is literally a murderer, but his actions will no doubt result in unnecessary and preventable deaths. I'm not sure what that does make him, but it isn't good.