Sure he dissented, but he's still feeding the big lie. Thomas wrote:

“That decision to rewrite the rules [of the election] seems to have affected too few ballots to change the outcome of any federal election. But that may not be the case in the future, [...] These cases provide us with an ideal opportunity to address just what authority nonlegislative officials have to set election rules, and to do so well before the next election cycle. The refusal to do so is inexplicable.”