Chris, those European guys are just trying out the woods that they have accessible. They're not claiming the woods they're re-discovering are better than osage or yew, just that they're good bow woods. They're free to think that laburnum and syringa are the best woods they've ever worked into bows, they probably have little experience with osage, being in Europe an all.
I couldn't find the TBB IV author you mentioned, I know several of them, and none of them posted on those threads.
The bothersome part about this post is that it brought up the unnecessary argument of osage vs the world, which wasn't the intention of the threads you're quoting.