Primark on the rack - the problem

I watched Panorama's investigative documentary, 'Primark on the Rack', http://news.bbc.co.uk/1/hi/programmes/panorama/7468781.stm which uncovered evidence that certain items of clothing made by Primark had been made using child labour and in incredibly bad conditions and for really poor pay. Primark were apparently shocked and very upset (not so shocked or upset that they actually bothered to speak to the journalists, but their press release said they were so it must be true)and immediately blamed the entire thing on a number of rogue suppliers which they then ceased trading with.

A whole lot of interesting questions were raised such as:
'How come Primark find it so hard to know what's happening in their supply chain when Panorama manage?'
'Is it even possible to make a £4 top ethically?'
(see here for a fuller discussion), and the programme provided lots of factual evidence but in the end left me baffled and confused.

'Primark on the rack' clearly showed that certain items had definitely been made in appalling conditions. It then confronted consumers with this evidence and asked whether they still got any pleasure from their sparkly £4 top or whether it would now stay at the bottom of a drawer. The teenagers were shamed into saying they would never wear the tops again and that it made them feel sick.

Then we were told that we, as consumers, must not turn our backs on the poor in Bangladesh etc so should carry on shopping in places such as Primark. Eh? So buy the clothes but leave them lying in the bottom of a drawer in shame? Or buy them and wear them but feel bad and maybe write a letter to salve our consciences saying we don't like children being used as labour?

Of course Primark shouldn't turn their back on the suppliers and should work with them to improve things, especially since it seems somewhat obvious that demanding clothes be made so cheaply and quickly means leads to the problem.

But why does that mean I should carry on shopping there? Surely it is better to buy something that is more ethically made? And surely Primark are more likely to care if they see a drop in profits?!