The move happened much too early to be called Dumbest ever. What if a man goes on to win? The effects of this move are so complex that we don't know if that man would have even come close to winning without it.As is, the move apparently saved Alicia or Christina. If a man wins because he already had or eventually forms an alliance with one of those two, who is to say that, for him, it wasn't the best move ever?
And throwing challenges has been done before. This is worse because it told Salani that Manono was divided but the difference isn't so great to call it dumber. The 4 original tribes that threw challenges; Sook Jai, Drake, Aitutaki and Zapatera all went into tail-spins after that decision. Of those 4 teams, only Aitu knew that there would be a tribal swap. This time, with a season starting as Men vs Women, Manono knew there would be a swap. The "Team" concept isn't as important then. And Bill isn't Russell. I'd therefore say that Sook Jai and Drake made dumber decisions but even those weren't the dumbest ever.
The dumbest moves ever still go to Alex and Erik.