I mistook your standpoint initially; it seemed you were implying you accept that Modern English isn't directly descended from Old English. Ambiguity would have been removed if you'd said: "Now that I know some Old English I find the assertion that Modern English doesn't directly descend from it hard to believe."Now that I know some Old English I find it hard to believe that modern English doesn't directly descend from it.
I don't think there needs to be any controversy over the ancestry of Modern English; the evidence for the extent of the contributions different languages have made to it is plain for everyone to see. It's partly a Scandinavian language, yes, but wanting to call it a Scandinavian language in the same sense as Norwegian or Danish is just fanciful. That said, I suspect nothing will unseat Faarlund and Emmonds from their hobby horse now that they've mounted it.