You've asked a broad, general question - I have no knowledge of Blizzard whatsoever.

But while in many (most?) cases layoffs have negative impact on morale, it's not necessarily the case. High performing teams and individuals can have their morale boosted if they perceive that unproductive employees have been trimmed. While perhaps less common in startups, I'd venture that in large corporations, there will be team members who are perceived to not be pulling their weight or are downright drain on the team; layers of management, not to mention bureaucracy and administration, that average employees would gleefully see removed; or branches that are perceived as diluting focus of the company -- etc etc.