I think his point was that, assuming that vegetarianism is ethical, hiding the abbattoirs etc may wind up increasing vegetarianism rates because when a sheltered meat-eater runs into them, they may be shocked into vegetarianism; while if everyone grew up raising their own pet chicken and slaughtering it themselves, no one would be shocked and they would all shrug upon seeing any video or photos.
I'm not sure this is true, since as the population urbanizes and specializes under economic growth, regardless of hiding animal suffering, people will inevitably not grow up slaughtering animals and will remain naively sensitive to suffering. So hiding then may increase the 'quality' of shock (more people who have no idea) but decrease too much the 'quantity' of shock (hidden means, well, hidden). But I have no idea how one would show this, and even if Goetz's suggestion turned out to be wrong, it's well worth remembering.
I notice that a large fraction of Effective Altruism people are vegetarian. This makes sense: in general Effective Altruists take moral issues seriously, even when that means changing your lifestyle. I'm not sure it's a good balance, though.
One way to think about this is to convert it into money. How much would I need to be paid to give up eating meat? All animal products? How much money would I need to spend on myself to be about as happy as I would be with less money but continuing to eat animals? I'd probably be willing to go vegetarian for about $500/year, vegan for maybe $2000/year.
It turns out you can probably pay to convince other people to be vegetarian much more cheaply than that. I estimate the cost of a vegetarian-year at $4.29 to $536 while Brian Tomasik estimates $11 with better methodology (which I looked at). This is by placing ads on facebook for a site where people can watch an animial cruelty video and ideally become vegetarian or vegan.
If you would get more than $11/year worth of enjoyment out of continuing to eat meat, why not give $11/year to convince someone else to not eat meat for you? Or give $50/year and be on the safe side?
(While you're giving money, you should probably give it to the organization that you think will do the most good with it, which I think is probably one of GiveWell's top charities. The nice thing about money as opposed to actions is that it's easy to redirect.)
I also posted this on my blog.