I can't imagine it's that clearcut.

What's the "intended purpose" for a general-purpose laptop?

Editing text, watching video, playing music, etc.., plus the long tail of more unusual things that may be possible depending on what software you install.

Are there any relatively common tasks that will actually be prevented by this level of ghosting? I don't mean "it's a bit annoying", I mean "this task is no longer feasible".

I've never used a computer with any ghosting that bothered me personally, so I may be missing something.

I'm not a graphic designer though; but neither is the author of the post AFAICT (PhD business student).

So my feel is that this is more in the category of a scratch on the bottom of a new laptop (doesn't actually affect the use, but annoys you each time you notice it and remember you paid full price) than, say, a space bar that only works 80% of the time (which would actively mar your ability to use the device).

So sure, Apple may not be playing this right to give their customers the appropriate warm fuzzy feelings, but I highly doubt they're doing anything illegal.