Your essay makes me think of a system where you have three things: a human welfare "bucket," values that control how much flows from human to animal welfare at a given time, and another animal welfare "bucket." And human welfare and values are long-term things, which at any given time feed into animal welfare. And you're saying that expanding the animal welfare bucket is not the best long-term intervention for the ultimate purpose of, say, maximizing the combined human and animal welfare. Given that we assume influencing the far future is possible, I don't see any flaw there.

but do you see practical differences between promoting animal causes in the short term and changing values to prioritize animal welfare?