If that was my mother and I had Anakin's power, I would have genocided the Sand People too, think alot of people would if they had that power and watched their mother die and knew of the torture and **** she endured. (didn't foresee that word being censored, but it makes sense) The reference is subtle but stop and think about why Sand People would have someone bound and gag. As it has been stated: the Sand People are savages.
Really? You would slaughter a whole camp of men, women and children? Well, that is your prerogative I suppose.
What you are doing is an example of what I was stating earlier, justification of character behaviour instead of examining whether the artistic choice itself is successful. The real question though is not what you would do yourself but what effect this plot device has on the audience and whether this is consistent with the themes and topics of the story.
I'm sure you would agree that a major theme of the story is that revenge, anger and hate are dark side emotions. With the act of genocide what we see is clearly indulgence in revenge and in his subsequent confession to Padme the overriding emotions are still anger and hatred. Why isn't this Anakin's fall? Why does Lucas just treat this barbaric act as a seed for control issues concerning Padme? Why does the story clearly indicate the Windu/Sidious duel as being Anakin's point of no return?
Is dismemberment for the sake of love really more of a dark side issue than genocide for the sake of revenge? Is the life of a savage child really worth less than the hand of a Jedi master? I wonder what answer Yoda would give to those questions.