We can 'answer' this one from the recent Ethics of brain emulation post:

[...] the nature of the emulation does not matter: if it is cruel [in real life] the same cruel impulse is present in [the simulation]. It is like damaging an effigy: it is the intention behind doing damage that is morally bad, not the damage. Conversely, treating emulations well might be like treating dolls well: it might not be morally obligatory but its compassionate.

Note: This reasoning depends on your ethics (in this kind kantian).