Interesting. I agreed with you until I realized something -- wifi is essentially broadcast radio waves. Unless the information is encrypted, there is not only no intent to hide it, but it is being actively transferred at you. I think a better analogy for sniffing unencrypted wireless traffic may be your neighbor yelling all his personal information across the street to someone in plain view. How is that supposed to be a private conversation?

Except that Google did not steal, they only warned people and shown that it's possible.

If someone got a key logger and logged your bank account name and code would that be considered stealing or "warning you what's possible"?

It depends on what he would use it for.