While I totally feel that moneylenders are a bad thing you have to remember that these guys cater for people who the mainstream banks wouldn't touch with a 10 foot pole and a rubber glove. They usually cannot get credit from anywhere and any extension of their incomes is usually welcomed with open arms since they generally have virtually no sources of credit apart from possibly the credit union. I do think you also need to remember that most of these loans are quite small (less than 1k) and usually colelcted person to person.
While its obviously wrong to charge such high rates of interest if the amount borrowed is quite small then the overall charge still isn't going to be very excessive. The problem with moneylenders is when loans are rolled over into new borrowings and they start getting larger. Its an exceedingly complex area, but its critical to remember that many of the borrowers are high risk and unlikely to get credit from other sources. To give you an idea, my friend who bought a house 6 months ago recently received a solicitors letter for a tenant of the previous owner, who was on social welfare, demanding back the 12,000 she owed them and presumably absconded owing. If the CUs are getting stung at that level then its likely that many borrowers will have nowhere to turn but money lenders.
Personally, by the way, I find it incredible that somebody on welfare can get that level of a loan!