Newspapers are financed by ads and subscriptions. Both categories drive up ad impressions, links, referrals, newspaper profile, etc. and even if somebody would drop out of subscription based on that the chance is very low. So as long as journalists can keep on this side of a complete fabrication (that could drive subscribers away in serious numbers and make advertisers think twice) they're fine with sloppy work. A good controversy only helps the bottom line, and they can always say "we might have been wrong in small details but we illuminated serious concerns of public importance".