[woodruffw]

I think the phrasing in this post could be better, but the basic observation is sound: if the last use of a weak hash function in your codebase is in HMACs, then it’s better to upgrade to a stronger underlying hash function and apply a blanket ban to the weak ones. Similarly, in a greenfield codebase, there’s no reason to pick an HMAC construction based on a weaker hash when collision-resistant ones are universally available.