They're not really giving a reason for engaging. They are indicating that they would like the membership to share the same views that they have of the overreach at the WTO. The challenge is that any time a legal question is put before the WTO, there is a winner and a loser. Finding agreement that the interpretations of the AB are inconsistent with the covered agreements is very challenging to do.
On March 11th, 2020. See this statement in context.