Because they blame one company. From what I've read Apple has done more than anyone else to improve the situation and yet they're the ones that constantly receive blame. Do a report on the supply chain as a whole and how the entire tech industry has workers that are being exploited. They select one company (a popular one) because it'll generate more clicks regardless of the fact that it makes the reporting slightly biased.

They don't blame one company. They did an expose of one company. And one of the companies with arguably the most popular product.

The company who's also arguably doing the most to improve the situation. If the journalist actually cared about what was going on they would expose all offenders and highlight the worst, not expose the one who's already been exposed by several other journalists and is working to improve the situation.

My heart bleeds for the plight of Apple.

It absolutely doesn't, which is why I put in that disclaimer. But focusing on one company will just make people say "well Apple products are made with slave labor, so I'll buy a Samsung instead" when the Samsung stuff is made in the same factory with the same raw materials, and it solves nothing.