I put no stock in these kinds of lists as they are usually created to generate buzz and controversy rather than try to rate musicians based on subjective and objective data.
I mean, Jam Master Jay is #10?

A lot of the rest of the list is made up of what many of my guitar playing friends would call a who's who of "Underachievement guitarists"; slackers, down-tuned-one-finger chord players, noise makers, etc...w/ Kurt Cobain as the king.
Sketch, as far as Hendrix...for years I didn't "get" him either. Just saw him as another drugged-up stoner from the '60s.
Then I watched a few documentaries and listened to the songs that they DON'T play on the radio.
I finally got him. He was an amazing musician, imho.