I do not believe it is a violation of privacy. Face book has actions in place where a user or poster has the choice of who sees their post. It can be shown to only a select few or a group of chosen friends. The post can be made public if the poster chooses. So it is not a privacy issue because the poster has absolute control over who gets to see the post in their news feed. The protections are there it is the users responsibility to use it.
No, Facebook's news feed is not a violation of personal privacy, because every person who signs up for a Facebook account knows that what they post will end up in a news feed. In addition, a person with a Facebook account chooses who to be friends with, so the information is not going to anyone they do not already know.