The OP doesn't claim the it was the peak of humanity, the claim is much tighter than that: it was the perfect balance of technology usage.
Almost universally, any time closer to today is better for most people in most ways than a previous time. But there are exceptions -- prehistoric hunter/gatherer lifestyle is superior in several ways to the modern one, but the risk of dying early in a horrible way is high enough that it's not true overall.
Should we live more like cavemen in very constrained specific ways? Probably. Do we want to force 8 billion people to starve to death by returning to that life? Heck no.
Similar, there are likely small parts of the 2000's that are better than today. That doesn't mean the 2000's are the peak of humanity.
"Almost universally, any time closer to today is better for most people in most ways than a previous time"
Wind that back 20 years. Yeah we got cheaper computing. Luxury items got cheaper, necessities got more expensive. I can make do with a 2010 think pad, but my rent is cooked and I'll never own a house. I'd rather be born in the 70s than the 90s.
20 years ago the average house cost 7-8.5 times the average income (cf 5X today). 2006 was the worst time to buy a house in America, ever. It was an exceptionally bad time because prices collapsed in 2008 and anybody buying in 2006 would have been seriously underwater.
You know what else you had in 2006? Loans, without jumping through hoops. "Being underwater" is the kind of thing people say when they look at their home as a thing they intend to make money reselling later. If you want to own the place you live, then you want easily-acquired loans and available inventory. It doesn't matter what someone else thinks it's worth, as long as you can pay your note.
You seem to have rose glasses for the actual situation. Many of those people with easily acquired loans have lost everything since the terms of the loans were as easily changed in 2009 and they could no longer afford the payments
The Iron Curtain had fallen; there was hope for Russia to become a democracy, and the weight of living in fear of dying in a nuclear war was lifted. China was becoming, perhaps not democratic, but at least economically liberal.
The economy was doing reasonably well for most people - it wasn't the high inflation of the eighties, and 2008 was not yet on the horizon. It wasn't yet the two-level economy that it became - if you were lower class, there was still a plausible route to the middle class.
AIDS was becoming manageable rather than a death sentence. Climate change wasn't really on people's radar as a real worry yet - there wasn't a sense of doom about it.
There was still hope that technology would free and empower us rather than enslave us.
And no, I wasn't a teenager or in my early twenties. Though I did have a pretty sweet life then...
For the international stuff, that's possible. Still... Russia wasn't an adversary yet, even in the early 00s. Neither was China. Nobody was building bomb shelters and doomsday retreat bunkers.
What is truly unfortunate is that even if there was an objective way of looking at history, people would just dismiss it as "oh, shut up, it's just nostalgia." Being unable to be objective doesn't invalidate the argument.
So what if the early 2000s were, in fact, the peak of humanity? It doesn't seem so absurd when teenage people today rediscover 90s/2000s fashion and are nostalgic for an era they have never lived in. When I was a teenager in the 2000s I didn't give a rat's arse about the 80s, they felt old and stale and with terrible hairdos. Yet today young people yearn for the 00s aesthetic [1] than whatever sanitised corporate hell we live in today.
Maybe people aren't nostalgic for their teenage years in particular, but for a world that wasn't ruled by the Internet and computers. When the Internet wasn't an infinite plane of corporate capitalism ruling the world, coercing people to jack in the hamster wheel every minute of their lives through their smartphones.
1: provided you are in the same algorithmic bubble of mine full of late teens/early adult people finding joy in analog experiences away from technology.
