This action has far more to do with protectionism than protecting intellectual property rights.
Far from leeching off newspapers and print journalists, aggregators are essential to spreading the word about important stories. They drive significant traffic, which in turn generates revenue for content providers. Its a win for both sides. For publishers that disagree, Google already includes a simple mechanism for websites to exclude themselves from search results. If the purported theft of content were truly the issue, that would end the discussion.
That it doesnt shows this tax is not a matter of principle, but of old-fashioned crony capitalism.