Zuckerberg has shown himself many times to be a very shrewd businessman. Ethics aside, he has been able to take decisions that are good personally for him and Facebook. The Instagram acquisition was probably the bargain of this century, and if you read the HN thread about it, a lot of the comments are about why it is stupid and the board should push Zuck out because he has caused them a big loss. Letting it go through is one of the biggest anti-trust failures.