Fair enough, the point of this was for me to find out what the objections were anyhow.
An adult never has their decision making compromised, at least not from the things you listed. She was an adult, it doesn't matter it he was her mentor. Would it be wrong for Eb to ask Harry for help? Of course not. It also doesn't matter that she was in love with him. Is it wrong to ask a spouse for help? I mean come on. And I reject entirely that black magic is real or works the way the WC thinks it does. The entire justification given by the WC is logically incoherent with regards to the laws of magic.
Notice your use of "I." Your conceptual gap is your fanon. You don't trust the White Council, or its understanding of how black magic works,
despite Harry agreeing with them on how it works and "taints" the magic of a wizard or sorcerer. Harry chose to make a Faustian bargain for selfish reasons- paternal love for a child. While sympathetic, it was in some respects the moral equivalent of having a child needing an organ donor and murdering people until a matching donor was found- that's what the "whatever" in "whatever it takes" means. Harry is going to kill whatever he needs to kill, and allow whatever friends and allies need to die to die, to save Maggie. He might feel bad about it later, but he's quite clear that feeling bad later isn't going to stop him now. That's . .not a good choice, from a strictly moral perspective.
It worked out for him. Intentions do in fact matter, not just actions. If my wife is having a heart attack and I run a red light because she's dying on the way to the hospital, but then run over a pedestrian, it is neither legally nor morally the same as slamming on my gas when I see a pedestrian walking to run them over laughing. One is Murder 1: Deliberate and malicious homicide, one is
negligent homicide or
reckless endangerment- I knowingly took actions I knew *might* result in the death of someone but neither intended them to result nor planned for them to result. It's why such distinctions exist. In fact, that's the essence of the self-defense defense Harry has vs Justin- Harry did not want to kill Justin, he wanted to not-be-dead from Justin, which required killing same. No malice or enjoyment, the intention was self-preservation.
Harry annihilated the Red Court- and the heroic Fellowship of St. Giles. Good with the bad. He didn't do it for the war, or even to save his own life- in that respect, *not* selfish. He did it for his personal child- not all the children the Red Court regularly killed. It was personal.
"Buts" are justifications, not validations.