In the comics, it's a complex situation. Different storylines might have different outcomes, but as of the common ones, no one has directly killed Homelander.
The wizarding community would be shocked. Guns are not part of their world, and for Harry to use one to kill Voldemort would be unthinkable for many. There would be outrage from some traditional wizards who believe in magic as the only proper way to fight.
Most of the fandom would probably be horrified. Naruto is known for his positive values, and killing a family member is completely against that. There would likely be a lot of criticism towards the author of such a fanfic.