I gotta disagree with you here. Maybe this is one for the unpopular opinion thread but I think you have every right to tell someone how to raise their children. The argument I often hear against this is "raising children is hard" but the way I see it, if it's hard, you should be taking every piece of advice in your stride and even if you're not following it, you should at least give it a chance. His daughter is eighteen years old, he is no longer legally responsible for her and her virginity is none of his business. I'm not saying he can't be there for her when she needs him, nor am I saying that sex trafficking/STDs/single-motherhood isn't a problem, but just because someone is having sex that doesn't mean they're in danger and it sounds to me like he's demonising sex when he could just be having a civil conversation about it with her. This whole "daddy's little princess" mentality is so backwards and all it does is regress young women instead of encouraging security, freedom and healthy father-daughter relationships. It may seem all very well and good now but how's she gonna fare when she has to be completely independent? Is she gonna have any idea what to do when she's faced with an adult issue or is she just gonna turn to her father to bail her out of every situation?
To clarify, I don't mean to sound hostile nor do I mean to attack you personally. In fact, I agree with your last few paragraphs... but if the generation before us can't take a bit of criticism when it comes to the way they parent, why should we take any criticism from them? This is why children don't listen to their parents, because many parents unfortunately feel like they can do whatever and get away with it because "how dare you question my parenting style". There's no such thing as a parenting style. Either you parent or you don't but how you interact with them on a personal level is dependent on you and I can't separate the way someone raises their kids from the way they are as a person.