I think the answer is pretty clear. The NY Times is cloaking content – i.e. a technique in which the content presented to the search engine spider is different from that presented to the users. The fact that some users can see the same content is a red-herring. For example, if I changed my agent to GoogleBot, and accessed a site that used agent cloaking, then that site wouldn’t be cloaking on the basis that some users (i.e. all those with agent = Googlebot) can see it? In any case, cloaking is mostly about the practical effect, which is that a SERP does not show me the same page that was indexed by the spider.
It is a good example of how cloaking can be beneficial to search engines, although, in this case, I find it annoying as a user. I’d prefer Google informed me that the content is only available via subscription, in which case I wouldn’t click on it.