Yeah that's some fucked up state the economy's in there. You're right; there aren't enough 'proper' jobs available.
I don't reckon it's necessarily bad database management though; I just don't think they do ever actually remove your details from their list even if you do ask them to. Sucks either way.
If I had a job like that though, I'd rather the person I was calling just walked away from the phone than slammed it down telling me to fuck off though. And it's not as if I haven't tried to reason with the caller and explain that I'm genuinely not interested in what they're trying to sell me. I do, I'm afraid, get really lairy when people just don't listen to me and try to tell me that yes I DO need a loan or to change my telephone service provider or update my double glazing when I've politely explained that I really don't want any such thing at the present. Pushy salespersonship really riles me...