That just means that they have a PR problem. It doesn't necessarily indicate a problem with their actual warehouse conditions, though there may be one; it's enough that people believe there's a problem.
But these adverts raise even more suspicion. I had a very awkward feeling when I saw them the first time in the German TV. Everybody knows that adverts are the poster-child of lying. Why should this be different? And if those are real workers being interviewed (I doubt that) who in his right would voluntarily step in front of a camera and say "this is a great and safe place to work". If they are for real, I'd think they are coerced. If they are not for real, what's the point?