Hi FGD. I take it you're pretty happy with Anthony Klan's article then?
Without trying to get into a point-scoring table tennis match, I think the two main start points for my argument (and call them speculation by all means, but not wild speculation a la Klan) are:
1) a thunderstorm probably caused the demise of the aircraft, and
2) you're better off going around big storms than trying to go over them.
Was Klan's piece presented as opinion, or as a regular report?
There's no clear statement that it's just opinion, and the clear implication with the quotes from the 'aviation expert' in question, detailed diagrams and so on is that the article presents authoritative information.
I would suggest it was opinion, in which case he has licence to speculate all he wants.
Perhaps the aircraft is with Elvis on the moon! Speculate all he wants - not at all. The style and content of the writing shows he doesn't know much about flying, and someone like that shouldn't be allowed to write half-page articles on aviation in national newspapers.