If Craigslist itself claims that it can and does screen these ads, then why is it out of bounds for CNN to point out that it apparently can't or doesn't? That'

If Craigslist itself claims that it can and does screen these ads, then why is it out of bounds for CNN to point out that it apparently can't or doesn't? That's not CNN "misunderstanding large-scale websites", that's CNN trying to expose a claim from Craigslist itself as false.