Larger publications, such as the WSJ would probably need several people working full time to deal with this situation, and still fail at catching many instances of infringement. In the case of an infringing article appearing on the front page of HN, that infringement leads to widespread unauthorized distribution.
You wrote in a different comment "HN would suck worse without NYT, WSJ, Economist, etc."
That argument is effectively: It is better to allow infringement, because the articles are worth reading.
Just because something is worth stealing does not mean it should be stolen.
Maybe if HN wants to contribute to supporting journalism – or at least finding a solution to the "problem" – you'll allow the "pain" of not supporting copyright infringement. Pain, after all, can be motivating.
No one likes the current solution, it's just that the alternatives would suck worse.
https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so...
https://news.ycombinator.com/item?id=10178989