If such a poorly designed system as a human has the ability to change its goals in response to stimuli, and we find this to be a desirable property, then surely a carefully designed AI will have the same property, unless we have an even better property to replace it with? The argument, "humans are bad, AIs are good, therefore AIs will do something bad" seems unlikely at face value.

(Note that I would like something that more reliably acquires desirable goals than humans, so still think FAI research is worthwhile, but I would prefer that only the strongest arguments be presented for it, especially given the base rate of objection to FAI-style arguments.)