That's just a bloomberg article, not a full cost benefit analysis. If some of the pig waste goes to the shrimps, less of it will go elsewhere. I'd call that recycling - a positive externality here.
Pig manure is causing problems in this world. For example, some serious effort is made to find the best storage temperature to reduce methane emissions - see www.engr.usask.ca/societies/csae/protectedpapers/c0209.pdf for exemple.
So anything that will reduce or convert the amount produced is a good thing.
Including contaminating food? What's with this straw man? Pig waste might be a problem but how does that justify feeding food sources with it? Are you comfortable with the notion of feeding other non-seafood food sources (such as pigs) with it too?
Again, all the context necessary is provided in the article. I'm not against finding a solution to the "pig waste problem." I don't think feeding it to food sources is a logically sound primary solution any more than feeding children radioactive waste is (for the "radioactive waste problem").
It's a solution. Until it has been evaluated, can't say if it's the best solution. It certainly is a way to consider however - like you, I'm not against any solution.
But the radioactive example is a fun one- wasn't there a plan to reduce the risk of radioactive materials by including them in construction materials, so that the emitted radiation would be lower? Some believed that it was safer than concentrating/burying them.
Pig manure is causing problems in this world. For example, some serious effort is made to find the best storage temperature to reduce methane emissions - see www.engr.usask.ca/societies/csae/protectedpapers/c0209.pdf for exemple.
So anything that will reduce or convert the amount produced is a good thing.