Both WSJ and NYT (maybe also other publications with a paywall) will display articles if you are coming from Google. Just entering the article title (article URL tends to work, too) into Google will get you there without any paywall. (I guess this is also why looking at the cache works.)
It’s a form price differentiation, really. Also, I’m guessing this is probably the reason why many are not aware of the paywall and link to these articles.
In this case alternative and equally good sources without paywall exist so it doesn’t make much sense to link to the article with paywall (but that might have been a mistake). However, I do not understand objections to paywalls in principle.
My objection is that people attempt to publicly share private articles. If you're a member of a private website (which for all intents and purposes, a paywall is), then by sharing it with the public you're assuming they can read it. Which without circumventing the paywall, many won't be able to.
Sure, some people will have subscriptions, others will have found the article unlocked in one form or another, but still I think it's pretty poor form to share something closed source, if you will.
