Now wait a minute - where and how would the 737 have to be hit by the winglet to be brought down
Looking at picture 2, there are, IMHO, two possible scenarios:
1) the part of the winglet that was sheared off hit the stab
2) the wing of the 737 hit the Legacy winglet and the 737 winglet (assuming this particular one has them) hit the stab.
While I'm not a heavy-iron driver, I cannot really imagine either scenario to be enough to bring a 737 down.