It's a matter of perspective. Your general example sounds like it's from the perspective of WeWork's CEO, who is obviously responsible for his decisions.

But what about the perspective of SoftBank's shareholders? If they're unhappy about this, they ought to be unhappy with the dealmakers at SoftBank for creating a situation where SoftBank is exposed to volatility of this kind.

Take an extreme example. If a VC decided to invest $1b in a lemonade stand run by a 7 year old and the whole thing falls apart, then yes I would blame the VC for not conducting proper due diligence and enabling someone who neither had the right business for $1b or was the right leader to execute on that business in the first place.

There's a difference between not preventing behavior and enabling it, with gobs and gobs of cash.