I'm just saying that Zaheer, while not a hypocrite, has edge's past the perimeter's of his anarchistic philosophy when he decides that a person (in this case, the Earth Queen) is the enemy, rather than the system. The distinction between the two is very meaningful.
And I'm not saying Zaheer is a lesser character for making this mistake, unlike Amon. Amon was a straight up hypocrite, who was only using the equalist agenda to cover his own. Zaheer mostly follows within the boundaries of his cause, but makes human mistakes, because it's much easier to vilify a person than constantly keep in mind that it is a system, invisible, untouchable, and abstract, that is the real evil he is against.
I wouldn't mind if they explored this a bit, but they simply haven't set it up. It would have been cool if Korra had, at some point in the series, questioned Aang's decision to let the fire lord live. Then Zaheer's choices here would be a meaningful thing for her to respond to. As it is, I don't even know if Korra would even care if he killed the earth queen. Not just because she was a jerk, but I'm not sure if she's bothered by death in general. The protagonists feelings are very important in matters like these. As it is, I'm ambivalent whether they have him kill her or not. It's not like Korra is going to learn anything from it either way.