Just food for thought here. I understand why this bothers you. However another way to look at it is that if someone copy/pastes an article from the paywall, there is a chance someone will then go and pay for a subscription. It has worked for me. All the great work from WaPo and NYT since the election has caused me to want to buy online subscriptions to both those news papers.
Another example was back in the day I used to get free music from all the online sources. The songs I really liked I would then go out and buy the album or single. This was before itunes let you listen to the first 30 seconds.
So again, it does suck for someone to get your work for free, but possible that you do gain a positive out of it.