Yes. Very sad. There's nothing like having the rest of your life to regret poor youthful choices. But at least they can look back and know that no one cared enough about them to warn them of the dangers.
Of all the "poor youthful choices" there are to regret, what number would you assign to "meaningless tryst[s]"? I mean you've got murder, stealing, fighting with the Taliban in Afghanistan, becoming a communist, burning down a house, having an abortion, poor eating habits, not exercising, taking up smoking, getting hooked on a daytime soap, flunking out of college, speeding, wearing stripes with plaids, etc., etc.
Tut-tutters and tsk-tskers wear people out with their endless preaching about nits.
Most folks grow up and move on. Very few are stuck in an endless cycle of sorrow over their youthful indiscretions. However, there is nothing more pitiful than to see 40 year olds, men or women, trying to live as though they are 19.
I made a lot mistakes when I was young, a whole lot. Thank God, I learned from them.