> It sounds horrible. But does it make sense? If it’s that bad - why didn’t anyone notice?

But they did! As you say yourself

> For many, this slowness won’t be a surprise. There are plenty of complaints about slowness on MacOS, especially around popular packages.

So this is some parody, describing as efficient something rather inefficient

> Because Emacs is very efficient.

> For instance, dragging a window handle - depending on the machine - could result in thousands if not millions of such events, causing allocation and reallocation of gigabytes of memory;