When I was a teenager “friends” was a big thing, and you couldn’t avoid it, everyone talked about it the next day - water cooler conversations.
And while I didn’t hate friends (then at least, for me it didn’t age well) I can appreciate that it’s inane. So negative criticism in that context makes sense because it occupied such a huge part of our cultural experiences, and with limited channels in network TV, it occupied a spot that you could argue should have been taken up by something else. And there were a lot of things that almost everyone was subject too, negative criticism was a way to process that.
Now, your own thing exists out there, to watch that, no one is forcing you to watch stranger things.
Also, I notice “Noah Schnapp” is a standalone bullet point here. Between this and Quentin Tarantino’s takedown of Paul Daño, it really feels like some people are mad that bullying people has fallen out of favor.
Second, there are only about two nerd kids in the show - Dustin and his girlfriend. Steve is a jock that saves a day. Both Byers are artistic. The rest of kids are normal average although somewhat introverted boys. There is a bookish girl, misfit skateboarder girl and "normal" gay girl. If anything, the show is covering all stereotypes that there are and paints them all in positive light. You can choose your hero that is kind of like you and feel good about the show. Even if you are an adult. Hopper is a flawed hero, Byers is stereotypical mom except smart and can fight.
That is, imo, another reason for the success of the show. No matter which stereotype you relate to, you can feel good about yourself. Unless you are Freddie, I guess, and feel like a show where nerds are not bullied by sociopathic jocks, but cooperate and befriend each other must be an aberration.