They live in countries where the cost of living and rental cost for pc and internet are low enough if they make a couple bucks off upvotes they are set for that day or even a week depending how much.
This is unfortunately a difficult truth... last site I saw destroyed by this sort of behavior... 95% of the "action" came from four particular locations that are now starting to show up here on Steemit, in some force. Cost of living isn't necessarily as much of an indicator as culture. Just look at the Nigerian contingent on Steemit... engaging, produce lots of quality content-- use the platform to make authentic differences in their lives. Same with much of the Venezuelan community. Certain other places, no so much... almost like cheating and "half assed" is a more culturally acceptable value.