“A pretty standard view of justice is that you don’t harm others, and if you are harming them then you should stop and compensate for the harm done. That seems to describe what happens to farmed animals.”
I think this only applies to people who are contributing to the harm. But for a vegan for is staunchly opposed to factory farming, they aren’t harming the animals, so factory farming is not an issue of justice for them.
I’m most interested in how Ashford’s views might affect cause prioritization. Yes factory farming and x-risk can be characterized as injustices, but it isn’t clear to me if these cases are as clean as the case for global poverty being an injustice. For example, you might argue that x-risk is caused by corrupt international institutions that only favor present people, but this brings up a whole range of possible considerations like if you can be unjust towards future people given the non-identity problem. Overall, I think this issue is debatable and I’d be interested in seeing more work done on it.