You're just going down the road which leads to the failures of moral absolutism. The conclusion is not that pain can't exist in a machine, or that it is wrong t

You're just going down the road which leads to the failures of moral absolutism. The conclusion is not that pain can't exist in a machine, or that it is wrong to torture a simulated being. The conclusion is that torture is not wrong simply because it causes pain, but because the pain it causes leads to otherwise undesirable consequences. Eventually you're going to have to decide what is intrinsically undesirable, which means understanding what your goals are before you ascribe moral value to some process. You can't say pain is good or bad without first understanding how it gets in the way of your goals.