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?