I do get what you're saying, 100%.
As far as the particular situation we're talking about:
Cora brought Brewer in in the 6th to face the 7-8-9 hitters. Brewer threw 15 pitches. He had thrown 15 pitches on Saturday as well.
Cora brought Walden in in the 7th to face the top of the order, using the philosophy that you use your better relievers to face the better hitters.
I can understand some questioning of why not stick with Brewer a little longer. But I can also see an argument for going to Walden.
The box of chocolates has become a box of dog turds, unfortunately.