Plot hole: The crux of the plot (one of the many plotlines, that is) is that Harry Osborn hates Spider-man because he refused to help him when he is quickly dying of the same genetic disease that killed his father. You can see the problem in this sentence already; he is a teenager, but he's dying super-quickly (he already has a large ulcer on his neck) of a disease that didn't bother him with severe symptoms before and that took away his father at 63. No reason is given of this sudden outburst in Harry's case, in fact nobody even acknowledges that such a difference exists.
Plot hole: Harry learned about Max Dillon watching the Ravencroft video that lasted just a few seconds; from that he can infer the hatred for Spider-man, but not much else, and he's instantly locked off his Oscorp account, and building, after that.However, when he meets Max, he also knows that he is the one who submitted the design for the Oscorp power grid, which is information he shouldn't have since he had no time nor opportunity to investigate further - plus, all data about Max has been erased, and he never got proper credit for that to begin with. (01:28:50 - 01:36:30)
Answer: Peter didn't set out to kill Electro, but he has to stop him somehow. Overloading him is pretty much all Peter has to work with in terms of stopping Electro's rampage. He doesn't know what effect it will have on his opponent, but he hopes that it will serve to stop him in his tracks, which it does. Had Peter set out with the specific intention of killing Max, that would indeed have been wildly out of character, but he didn't - he simply did what he had to do to stop him. It's unlikely that Max is actually dead anyway; it's well known that Sony intend to bring the Sinister Six into play in upcoming movies and Electro has been a key member of most incarnations of that team, making it highly likely that he'll be back.
Tailkinker ★