Whatever Fell’s mistakes were here and there, he wasn’t a fraud. Anyone who says he was simply doesn’t know what they’re talking about.
I know nothing about ancient Irish writing, but that rebuttal pointed out very convincingly that experts agreed that Fell’s claiks regarding the WV caves were completely illogical and without merit. From what I read, one would have to suspend disbelief to make Fell’s theory even plausible. There is some solud evidence of a pre-Columbian European presence in North America, but those cave etchings ain’t it.