Well it also depends which matrix (if they went through a conversion to RGB at all) the frames were initially decoded with, of course. What you tell the encoder doesn't make any difference to the encoded video data if it's being fed YUV (as most are); it's just a hint stored in the container which will hopefully be taken by any eventual decoder. I've always got expected results out of YouTube if the video encoded was matrixed from RGB with rec.709, incorrect results with rec.601, and no knowledge of any other way to confuse colours.
Out of curiousity, are any of the wrongly-coloured ones (with a corresponding correct version on Vimeo/Facebook) still up on YouTube?
That image still looks nice though. I like how sharper it is comparing to original.
You could take any frame from any blu-ray, sharpen it, compare them on a computer screen and it will look "nicer." It doesn't necessarily follow that you can make a better video that way, though - it's a bit like the loudness war for video, with the added complication of wasting bits encoding sharpened pixels which your TV could have done for you at no cost.