Morality is a difficult thing to quantify, and the more we try to quantify it the more difficult it becomes. Although everyone agrees that killing people is wrong, not killing someone about to kill someone else is also immoral. But at a certain point using excessive force is immoral too, even though the goal is to do something moral….like I said, it’s difficult.
The logical fallacy of appeal to morality comes into play when morality is used to defend a particular point of view or silence another point of view. In other words, no moral person would ever hold opposing views to mine. No moral person could ever defend Israel’s aggression against the Palestinian people. No one could define themselves as a Zionist without losing their humanity.
Of course, the problem with this argument is that it changes the nature of the discussion from the issues (where it belongs) to the people talking about it. Therefore, it’s really just an ad hominem attack in another form. If the target of the attack isn’t shamed into silence, then it turns into another flame war: “You’re immoral! No, you’re immoral!” and so forth. If you are the target of this argument, be aware of this and react accordingly.
Similar to this is the appeal to pity. Both sides use this when they wave the bloody shirt, though in my experience on the HP Palestinian supporters do it more. Here’s how it usually goes:
“Israel’s attack on Gaza was an overreaction, but you can’t expect Israel to sit there and do nothing while Hamas puts their people at risk.”
“How can you say that? Don’t you know about the suffering Gazans? How about all the homes destroyed? Or the children who were killed? Don’t you feel bad for the Palestinians?”
“Of course I feel bad for the Palestinians but that doesn’t make them right. If they didn’t want war, they shouldn’t have started one”
“You’re just a soulless monster!”
We see this very often when the HP publishes blog articles by Palestinians about life in Gaza and the West Bank. And we would hear it if the HP ever published Israel’s point of view about life in Sderot. The trick is being aware of the suffering of the people involved in this conflict without letting it affect your judgment. But of course that’s the point of waving the bloody shirt, to cloud the judgment of your audience.