The overall quality of this website I'd estimate at least in top 5% of all Web, if not top 1%. The content is superb, the presentation is quite clear.

I was not referring to the content or quality of the page, just the technical sophistication of the presentation, which is at odds with the number of invasive popup ads. It just doesn't seem to be the type of site that would do that, yet here I am with 4 separate banner ads and a popup.

It's an http page, so your ISP//any hop along the way is free to insert anything they want or completely rewrite the content as they wish.

I turned off my adblocker and I see two inline ads, nothing crazy. Not sure what you’re seeing, but I’m quite sure you should install an adblocker.

Yes, adblocker makes it look like I'd expect. Someone along the way is definitely inserting ads, and likely b/c it's http://

If I stop uBlock and shrink the window / enlarge the text so only the main column fits, there's only two inline ads. At normal desktop size though, there's also two sidebar ads and one overlapping box at the bottom. And the ones I got move.

They look like legit AdSense ads, and there's a "liquidnitrogen" comment on one of the related scripts.