If that is true, why don't they have robots already? I know they are planning[1], however that kind of work seems to be very easily replaced by a robot (who will have a far higher accuracy and less failure rate than humans especially for the task the journalist describes).
But for this PARTICULAR example, is it cheaper? I know a bit about robot hacking, not industrial mind you, but this would be a rather trivial machine which could probably replace that entire production line? You might know more than me about it though :)
I know a bit on automation, work R&D in a factory. There's no doubt that it's cheaper in the long run, even with costs related to programming, testing, maintenance, and tweaking. But rushing untested robotics into production will almost certainly increase the costs above manual labor. It's better to maintain the current line while you test out the automation, gradually train workers to monitor systems, and switch over one line at a time. This particular story (painting dots) seems like a great case for automation, so I'd suspect they're working on it.
Also keep in mind that sometimes, manual labor trumps robotics. Let's say there will be 70 million of these backplates shipped, and then no more will be needed. That's a lot of automation investment in a solution for a temporary product. Workers can move from one task to the next with ease, while robotics require a lot of development, logistics, and testing. For a company like Foxconn that will always be manufacturing different things, the investment in human labor might allow for more "pivoting" than robotics. Comes down to what makes the most business sense for them.
[1] http://spectrum.ieee.org/automaton/robotics/industrial-robot...