—into committing every sort of mistake, adducing what is no evidence whatsoever, and flouting the explicit proof?!

So, by Allah, how astounding! In what conceivable way does this ḥadith indicate the validity of a muḥallil? Where is its force—on any reading—in your favour? Is not a report like this (1) nothing but a proof against you?

For the Prophet ﷺ first (2) said: “Shoot, for I am with the clan of so-and-so.” He did not ask whether both sides had staked something, whether only one of them had, or whether neither side had offered anything. That shows there is no distinction, as far as the permissibility of the wager is concerned.

Moreover, a muḥallil never belongs to either of the two teams, nor may he say, “I am with So-and-so,” or “with this team (3) but not that one.” That is simply not the function of a muḥallil; and your attempt to use this ḥadith will not stand (5) unless you first establish several points:

First, that both teams actually put up a stake, that the Prophet ﷺ knew this, that he joined them without staking anything himself, and that in doing so he served as the muḥallil.

Even if one does not decisively dismiss this claim outright—if its falsehood is not cut off (4)—it remains a mere allegation devoid of any proof from Allah or from His Messenger ﷺ, and therefore merits neither a hearing nor acceptance.