I think you either misinterpreted the employees's comments, or they were mistaken. Our deletion policies are clearly outlined in our privacy policy (Snapchat.com/privacy).

"...we automatically delete the content of your Snaps (the photo and video messages that you send your friends) from our servers after we detect that a Snap has been opened or has expired."

Note that the deletion model is different for non-Snap media:

"Outside of Snaps, the rest of our services may use content for longer periods of time, which means those services may follow different deletion protocols. So, for example, we retain your Story content a bit longer than Snaps so that your friends have more time to view your Story."

Disclaimer: I'm an employee of Snapchat.

And nobody cares? Sexting is an extremely minor use of Snapchat nowadays, and everyone knows you can just screenshot.

Do you mean indefinitely? Are they not deleted after a certain period of time?