What?
How is it consistent?
We have a character up until this point who has had no emotions, no sign that he's ever had any, and has always been eager to explain things, perhaps in more detail than was absolutely necessary. And now, he decides that an EXECUTION is the only possible course of action, despite the fact that Fajo was unarmed, and then he refuses to say what was really happening?
In what universe is this consistent with the way Data had been written or portrayed up until that point?
Do you really want to do this?
In season one's Datalore, Data tosses his own 'brother' into a transporter beam that was focused on open space and had no problems doing it.
Then we'll look at this exchange from Skin of Evil, that you've consistently ignored...
Skin of Evil said:DATA: Curious. (the phaser drops) You are capable of great sadism and cruelty. Interesting. No redeeming qualities.
ARMUS: So what do you think?
DATA: I think you should be destroyed.
ARMUS: A moral judgment from a machine.
Data isn't as morally "righteous" as you'd like to think he is.
Oh really?
Yes, let's take a look at them...
First off we have Lore, who is strong, intelligent, and most importantly, armed with a phaser with the intention of using it. At the point where Data throws Lore into the transporter, a clear risk is present. Lore is armed and is in the act of firing when he is beamed out.
Does this come close to what happened with Fajo? Let's see... Lore was armed, Fajo was not. Lore was in the middle of an act of violence, and Fajo (when Data moved to kill him) was not doing anything except making vague threats.
Completely different.
(Oh, and let';s not forget that Lore was beamed out intact. He wasn't killed, just marooned in space.)
And what about Armus? Well, Armus had demonstrated that he was pure evil, and he had demonstrated that he could easily kill. The fact that he killed Tasha without motivation proved that he would always be a serious threat. Data's remark that Armus should be destroyed is justifiable in this case. And again, does this compare to Fajo? Well, on one hand we have an entity that is pure evil and possesses the ability to kill with a thought. And then we have Fajo, who, from the way he acted when he killed Varia, had probably never killed before, and was without any means to carry out his vague threats.
Does it compare? No, doesn't come close. Oh, and bear in mind that Data doesn't actually make any attempt to kill Armus either.
So do you really want to argue that a small unarmed man who is making vague threats is comparable to a creature of pure evil that can kill with a thought, or an insanely strong and fast android with a fully functioning phaser that is in the act of firing at someone?