Unreliable narrator? Or perhaps we are ill-educated readers?
The source and mythology behind the stone-giants is most likely
River Legends, 1875 by Edward Knatchbull-Huggesen (one of Tolkien’s favored authors) and the tale of
The Giant Bramble-Buffer. Within that story we have colossal rock throwing mountain giants who are also characterized as shouting a lot and depicted to kick folk high in to the air. Those constituents match up splendidly with attributes featured by
The Hobbit stone-giants, as does them dwelling in the Swiss Alps which correlates to Tolkien’s 1911 alpine journey (to which he professed inclusion of elements).
I’ve recently dealt extensively with what I believe is the fairy-story behind Tolkien’s stone-giant mythology as well as a ‘decent’ real-world source of the Carrock (again, from Tolkien’s 1911 adventures) on a ‘sister’ website:
http://www.lotrfanaticsplaza.com/for...pic.php?t=1165
Along with stone-giants, there might be a ‘reasonable’ explanation for those discordant troll names:
https://priyasethtolkienfan.wordpres...lorful-pair-4/
So perhaps we should not be too hasty at judging our very learned Professor!