I have a lot of time for Southall and what he's trying to do.
I think he's ended up being used and held up as a poster boy for issues on which he's out of his depth.
But I do believe that this all started out of a place of a genuine desire to be educated and to make sure he was doing right by the children he was coaching.
From what I can recall his involvement in this debate started with a tweet that essentially said something along the lines of "I'm an old footballer from a different generation, more and more I'm encountering children who identify as trans. I don't understand any of this can people help me so I don't end up accidentally further marginalising these kids". And I think everyone was quite taken aback by someone using twitter to say that they were confused, under informed and needed assistance rather than stating an opinion as fact and blindly defending it to the end regardless of any counter points.
Unfortunately twitter is twitter and it being what it is you're much more likely to get caught in a pro trans information loop and get praised by the online community for embracing those ideals than a gender critical one.
I do think there's something to admire in the intention of someone saying "society has moved on from my day and I want to move with it and treat others well" but I think the positive feedback loop has left him in the same position as I see in a lot of the younger generation whereby anything other than 100% acceptance that TWAW means you're a raging transphobic bigot.