There will still be plenty of people not following along with these chastity vows. I just don't see why people would make fun of it. Like most organized religion, it's just a good way to promote good health and welfare for it's followers.
This conversation will probably deteriorate into talking points based on what end of the religious/political spectrum you are on, but if that happens I'm bailing out and not taking the blame. However, like most organized religion, I see it only as a bad thing that promotes bad health and poor welfare.
The urge to reproduce (have sex) is much too strong to be squashed by fairy tales and dances. The best you can hope to do is to psychologically terrorize your cult followers at the expense of their mental health.
I make fun of this simple minded approach to dealing with real world concerns over health and welfare by peddling lies and fairy tales because that sort of behavior deserves to be made fun of.
If you are concerned about STDs, then have a discussion about STDs. If you want to promote healthy relationships for your children, then model healthy behavior yourself and talk openly and honestly about it with them.
However, more than anything else, these ridiculous displays of stupidity are made fun of because no matter how many times they are shown not to do any good (at best) or actually produce an increased frequency of the behavior they are trying to discourage, these people keep right on doing it. They don't care if somebody sat down and explained to them that they are not getting the results they are hoping for, and that there are better ways to do it, AND that they may be making the problems they are trying to avoid worse with fairy tales and guilt based teaching methods.
Actually, I believe they are not at all interested in achieving a good outcome for their children. That is not what this is about at all. It is about doing something that feels good. It is about the parent *FEELING* good about their parenting, not about actually *BEING* a good parent. It is a simple formula aimed at the lazy and the self-absorbed with minimal intellectual abilities who don't have the interest, commitment, or capacity to do what could really help their children and would rather just dress up, go to a dance, and tell each other fairy tales. Having frank, open, and honest lifelong communication while modeling appropriate behavior is hard work and exposes simple minded hypocrites to negative feelings of being inadequate. Buying your little girl a ring and taking her to a dance is easy and makes you feel good.
They deserve to be laughed at and scorned and marginalized in a modern society.
They deserve it because what they are doing doesn't work.
They deserve it because what they are doing often exacerbates the things they are trying to avoid.
They deserve it because there are other things that can be done that work better.
They deserve it because it hypocritically denies reality, science, and human nature (as was already experienced by the adults involved) and is being forced on trusting and naive children who deserve better.
They deserve it because they are going to pass off their damaged and brainwashed children to a spouse and a society who will spend a lifetime either trying to undo that idiocy or else deal with the repercussions.