For the same reason some diabetics let toe or foot wounds go until they have to have something amputated: they lack understanding of and/or underestimate the severity of their condition.
I understand that, but are there easy tests for detecting Leprosy? If there are vaccines I assume that those vaccines are the traditional vaccines which are proven to be safe. I need to look up this disease and do some research on it.
Honestly, this whole thing and scare is a lot like The Office episode where Michael Scott sets up a charity race for Rabies research, despite Rabies already having a cure. Basically, wash your hands and see your primary doctor every year (and a dermatologist every couple years for skin cancers), and you should never have to worry about leprosy. You probably don't really have to worry about it even if you don't do those things unless you regularly play "tickle the 'dillo" in your spare time.