Indeed. Just knowing that the subjects who followed through with the shocks were less likely to obey the rules could be interpreted in many ways, some invalidating the results of the experiment, some just suggesting a mechanistic explanation, and some making the results even more concerning.

* Did the subjects who went full voltage stop caring about the "learning" protocol because they realised it was all fake? Then the conclusions of Milgram's experiment are invalid.

* Did the subjects who went full voltage make more mistakes because they were more anxious and fearful of the experimenter? Then underlying fear might be a mechanism for blind obedience, and further research would be interesting.

* Did the subjects who went full voltage just enjoy electrocuting the dude so much that they stopped caring about asking the questions correctly? Then blind obedience is the least of our worries, widespread sadism is much more concerning.