The problem is Google has already indexed most of them without asking. Therefore, Google has the advantage of having content from various news sites already in place, and the un-indexed sites are at a disadvantage because there are other indexed sites. The option to be excluded from the index would only have worked had Google never orignially indexed any news site without explicit permission. I realize the purpose of a search engine is to index sites and direct people toward those sites. However, Google seems to have reached a point at which it has become a content provider, displaying content from these sites and never actually directing people toward those sites.
To some extent, they seem to be doing the same thing Gracenote did, indexing content from many sources and ultimately profiting from that content with little to return to those contributors.
Try not to miss the point, that Google seems to have gone from a search engine to a site that actually scours the internet for content for itself, rather than directing people to the sites the content came from. I am not saying no site ever gets additional views because of a link from Google. And note that every anti-Google comment gets modded away, regardless of the validity of the comment. You may or may not agree with the validity of the comments in this post. But every anti-Google comment gets modded away, not just this one.