Barbie's got a dangerous addiction to endangered Indonesian hardwood, and Ken isn't putting up with it anymore. Once he found out Mattel packaging uses wood from the fragile Indonesian rainforest, at least some of which is from evil conglomerate Asia Pulp & Paper, he was out of there, girl.
This video leans a little hard on the "Ken is gay or at least metrosexual" trope, which is dumb because a) yeah, like we need more entrenched gender roles ("OMG, boy + doll must = stereotypical swishy gay guy!") and also b) Ken has no genitals, so can he really have a sexual orientation? Also it implies that Barbie is personally shooting orangutans in the head execution-style, which is maybe a little over the top (I'm not even sure they make guns that fit Barbie's hands). But the point — that Mattel sources its packaging from companies that illegally plunder Indonesia's rainforests — is an important one.
Here's another video with more information and a dancey beat:
Greenpeace has more information about contacting Mattel and donating to rainforest protection.