Chapter 8 -The Potions Master
"Ah, yes. Harry Potter. Our new — celebrity."
It's only fandom. It's not important.
Book Six: We get to watch Teenage Gryffindor Dating Games and Flashbacks of Tommy Riddle's School Days while the emotionally gripping stories are happening off-stage to Draco and to Severus.
Book Seven: Harry goes camping in the woods (for months!) and and obsesses over a brand new set of gimmicks we've never heard of before, while the actual war is being fought off-stage by Neville and by Severus at Hogwarts. Snape turns out to be a good guy, but only because he loved a Pure and Noble Gryffindor Woman (who treated him like dirt), and Voldemort dies because he didn't have enough sense to drop a piano on Harry's head instead of using the same spell that has never worked on the kid yet.
I feel like this is an overreaction to Deathly Hallows. Calling Lily's relationship to Snape as if she treated him like dirt is a bad faith argument with the context that they were best friends before they were accepted to Hogwarts and continued to be for 5-6 years, she even defended him from bullies on his behalf. It's only because of Snape's personal issues (exacerbated by his unhealthy home and social life) that attracted him to the Dark Arts and Death Eater ideology (as long as you belief, you belong and have community). Lily and Snape's relationship snapped into disrepair when he called her "mudblood," at first glance it seems like an overreaction on her part, but greater context reveals it was a growing problem until calling his best friend a wizard slur became the final straw (it would be like someone who is Jewish watching their best friend attracted to Neo-Nazi ideology and is helpless to do anything about it).
"But she married her best friend's bully!"
Well, even Harry was shocked to find out his dad was an asshole when he was his age. But Sirius and Lupin told him, now that they can look back from an adult's perspective, that he's right, the Marauders were assholes when they teens (which is a universal truth with most teenagers). But James grew up, as all children do; they mature. It probably began when he learned Sirius was leading Snape to Wolf-form Lupin, and realized it was joke that had gone to far and saved Snape before the latter got killed or injured and stricken with lycanthropy. And his straightening out, becoming better, foils Snape as he got worse with age. If things were different, maybe Lily and Snape's relationship could've blossomed into something more, but sometimes, some mistakes can really cost you.
As for Voldemort's death, it was kind of the point his ego was his downfall. He knew he was the smartest wizard of his age, but didn't count on the idea of others guessing his plans or being assured in his own power which was why he insisted on being the one to kill Harry or using Avada Kedavra (it's also implied that this is Voldy's idea of being "Master of Death" since most serial killers are fascinated with the concept of having the power to take life and be death). Strip him of all his mystique and fury and Voldemort's essentially an edgelord bullying teenager given power without knowing restraint.