You honestly think that unemployed people should be obliged to bolster a companies profits by being forced to work well below minimum wage?
How is that, in any way, shape or form going to lead to gainful employment? There is no qualifications gained, no real experience gained (shelf stacking is not experience. It is no different to filling my tin cupboard), and while your doing that how exactly do you search/apply/interview for a real job?
It's not creating jobs, in-fact it's the exact opposite. Need some unskilled labour? No problem, the government will provide it for next to nothing. Why on earth would you actually hire someone? No matter how much you need that staff, how much profit they will generate, even minimum wage will not compete with free.
They should be put into schemes that help the community, but aren't normally done directly by the council or a company. A good example I saw just this morning was a small village having a team of volunteers fitting broadband (fibre under the ground an all) since neither BT nor VM saw it as profitable enough to do it. It is an obvious bonus to the community, no one is making money off it, and there are genuine skills to be learned.