This is certainly the first level justification, but it's somewhat unusual isn't it? Find the most repressive regimes in the world and there's a good chance you'll find most of the big western names happily advertising and helping sustain the regime. We could argue that perhaps it's companies working to satisfy the market, but the people that work to call out advertisers are most often a very tiny minority of all customers. And in any case things like boycotts rarely last longer than the 10 seconds it takes for a new controversy to erupt on social media.

So what is their aim? The only thing I can frame it as is a power play. Advertisers working together to collectively ensure they have more strict control on what they can be advertised on has the nice side effect of them getting to decide the fate of many companies dependent on advertising for revenue. If a company acts in a way contrary to the interests of advertisers, they thus gain the ability to destroy that company. Similarly, it allows them to elevate companies that further their interests. Put another way, I wouldn't expect a documentary detailing the behaviors of Coca-Cola in South America or Nestle's behaviors... anywhere... to see much in the way of funding. But a documentary detailing healthy at any size? That's some advertiser worthy content.