That as well as the blatant reveal of his abilities. Xebec doesn't strike me as the type to make up specific shit. His arguments just seem him not being able to convey or explain his abilities accurately, rather than making shit up on the spot. The most dangerous thing about him as far as I can see is that a misuse of his abilities could result in another dead townie.
I think Hayumi and Xebec are mirror images of each other, except Hayumi's first language is English
He could have easily argued, what was even the worst case against him? Jumping on the vote Cooler bandwagon? Didn't a bunch of players do that?