Because they don't use it.
>We're talking about 50% ownership of a messaging platform that's de facto standard in multiple Asian countries
Yeah, except Korea. If they think it's so great, why aren't they using it themselves? It seems hypocritical.
>Imagine the UK government trying to force Google to sell DeepMind.
Does Google or anyone in the US actually use DeepMind? If so, that's a poor analogy.