Whether I like it or not, agree with it or not, I can understand why Google would be doing this.

For one, by sharing privacy settings between platforms, they are streamlining their policies. This is inconvenient for users who may have different privacy settings for different platforms, but makes life easier for Google.

In terms of the allegations of anti-competitive behavior, Google likely has taken a calculated risk here. They may one day face penalties for this behavior, but in the meantime, their current set-up encourages adoption and usage of G+ and other new products amongst consumers, and definitely amongst businesses. In the end, the growth in business achieved through this strategy would probably compensate - and then some - for any future penalties they may face.