Your have completely missed the reason for the alternate ending in I Am Legend. In the book 'Neville' is killing the vampires all day and sleeping at night (the opposite of the vampires, who sleep all day and come out to wander about at night). He kills the vampires presuming them to be a threat despite their relative humanity, (as displayed in several scenes in the film). To the vampires – Neville was, to them, the monster, senseless killing machine. Matheson (author) uses the final words, 'I am legend', to show Neville's realisation that his morals, taken from his previous world, made him a terror in the new world….

The alternate ending is closer to the books intention, and the final cinema release is a muddle of the two extremes the hollywood intention and the books intention. The Alternate ending clears up some of the plot points installed in the film that hinted towards a more humane society.

So to conclude, Miss the point much?