"They need to boycott all phones and tablets if they are true to there convictions"
No. "They" don't need to do anything, if you mean consumers.
Apple, as well as the rest of Silicon Valley need to stop with the happy talk in the bubble. Slavery is a systemic result of Capitalism. This has never been addressed, only reinvented (going on 5.000 years now). There is no other end game to the Business Model - manufacturing industries get there eventually. Left all to themselves, Silicon Valley reinvented slavery in Asia and indentured servitude in the valley itself (lawsuit about "poaching employees"). Again - all by themselves!
Where is Sir Arthur Conan Doyle when we need him ?
The crime of the Congo (soon to not be a Hollywood Movie, out of Copyright)