This is known as the 'broken window fallacy'. It says that if I go around breaking windows, jobs to fix windows will be created, and the economy will benefit. But really, what's happened is that we're living less efficiently. Houses with windows become more expensive, since the windows must be continually replaced. We waste effort fixing them that could have been spent on something with benefit.
The same is true when you make a factory less efficient. On the extreme side, we could require all workers to have one hand tied behind their backs, tripling the number of jobs created per factory. But the money those workers earned would be worth a lot less, since all goods would be much more expensive.
To put it as simply as I can, which society has more poverty: the one where they keep all of their harvests and GDP output, or the one where they incinerate two thirds of it? Because destroying two-thirds of it is equivalent to working at 1/3 efficiency.