I have made this mistake a couple of times, and many more times I have been about to make such a post, realized that I was not in the right chat, and just gave up on posting because I didn't want to take the time to retype everything I had written all over again.
It would be an incredibly easy fix to change it such that the "View all chat" button, when clicked while viewing the chat in another league's standings, would take you to the chat of that league rather than your own league. Such a simple change is something that would alleviate frustration of many owners, and foster community involvement. Taking the small amount of time needed to fix this, while a minor problem, is exactly the type of little thing that makes the overall experience more enjoyable.
Even better would be to allow you to actually type on the standings page itself, like you used to be able to, but that might be a more difficult fix given the redesign, which, while I still think is worth doing to foster more chatting in general, may or may not be enough of an effort to move it far down the list.