Unnecessary for your personal survival? That's true, but it's a very limited perspective to take. Cockroaches are known to affect our species' health adversely (e.g., http://www.ncbi.nlm.nih.gov/pubmed/11240940). If you wish to reduce their and other insects' unnecessary suffering without compromising the interests of humans, a better thing to advocate for is that we use more humane pesticides (http://effective-altruism.com/ea/nx/humane_pesticides_as_the...), not that we refrain from killing them.
You move in to a new apartment. Your first night, at 2 am, you hear a noise. You turn on the bedside lamp and see several cockroaches scurry under your bed. What do you do?
I used to live in India, that's the norm. We lived with them. The trick is that there's other things that eat cockroaches, that we also lived with, so it doesn't get too much of an issue. A house is part of an ecosystem, not a sterile environment.
For the record, it's almost guaranteed that any rice you eat in India has had cockroaches in the rice sack. Not a lot you can do about it. That's why we wash and cook things.
Now, admitting that I'm largely ignorant about conditions in India, and recognizing that it's a very large country with wide variations--is it not the case that public health in India is generally worse than in more developed nations where e.g. cockroaches would be considered a pest to be eliminated, partially for health reasons? If so, could that attitude toward them be part of the reason for the worse public health? I'm asking out of curiosity; this is not an assertion. :)
Quite possibly. On the other hand... we have immune systems for a reason - I see people in my developed country now who seem to become ill every month, and I do wonder whether our insistence on keeping a close-to-sterile environment has something to do with that. And in any case, there's more pressing issues like the general lack of clean water, even in many cities - all water should be boiled, but that doesn't always happen.
Why would you not seal the sack? Seriously. That is what I do with food if I know there are roaches in the neighborhood. Trust me, no roaches are getting in my food.
They're great huge sacks of rice - you can maybe fold over the top, but short of putting duct tape over it every time you need more rice, there's no sealing to do. I'm sure many people do that anyway, but I wouldn't trust many restaurants to, nor many shops.
