Thanks Kevin! You pose a great question, and I'm not sure about the answer. I'm hoping to learn more as I get further along with this. A few hypotheses come to mind:

• The large meat companies are the most powerful voices in the sector, and they have interest across all types of animal products. In particular, they have a lot of influence in the NCBA, which is the main group that one might think would be interested in these arguments. 
• Cultural factors that define the space of possible things that one could do to help ranchers. Similar to why I haven't really heard about this strategy from the animal welfare side of things, despite it being (as you say) pretty straightfoward.

It seems like there's recently been a noticeable uptick in the quality and quantity of animal-related posts by group like Rethink Priorities, Animal Ask, and many others. This puts the movement in a much better place than just a few years ago where it was very hard to know how to effectively help animals.

Just wanted to say this is awesome, and keep up the good work!

Thanks for doing this important work! I think this is one of the most important findings in animal advocacy research, so understanding it deeply and accurately is critical.

My operating model of the underlying psychology is that "slaughterhouse", "factory farm" and "animal farming"  can suggest to varying degrees the idea of "place where animals are treated poorly." People  generally don't want animals to be treated poorly, so they express support for banning such places. Then, if it's made clear that, in fact, slaughterhouses are just where animals are killed for meat, this support goes away.

If we think of people as being pro-animal welfare, but also pro-meat, all the data is explainable. As activist, it can be easy to go from "animals are mistreated on farms" to "we shouldn't eat them," but for most people I think the more natural response is "The people mistreating them should stop."

Just wanted to throw this out there, since I think all this data is still consistent with a surprisingly pro-welfare stance of a lot of people :)