[vurpo]

It's a reference to an old HN comment back when the creation of Dropbox was announced here. Someone commented something along the lines of "you could just" do that whole thing with the FTP server etc. It's lived on as an example of "peak HN" attitude.

[vanderZwan]

So any form of disagreement with someone can be reframed as being dismissive and missing the point, and therefore "peak HN".

That's quite the non-starter for any discussion about whether an idea holds up under scrutiny.