I don't see the correlation between you and your "girlfriend" having sex at daddy's pool when she is not your instructor, versus a teacher/student relationship where the teacher has been to university and likely taken courses in philosophy, higher mathematics, and English literature which is full of sexual analogy and suggestion.
The student in this case is likely a drug user who has an underdeveloped frontal lobe and amygdala based on that possible drug use and the level of education he is currently in.
These are huge differences in the educator and student. In this instance, I am leaving out the idea that she is supposed to be his educator, and as such trusted to teach him things he needs to know to get himself through life in as productive way as possible. I guess the experience of sex was meant to help him learn how to get a good woman who has a good education and tenured position with a company that pays her a healthy salary. That way, she can take care of him?
What argument can you possibly make that makes any sense?
Earlier you asked what should be done to protect teens and also weed out abusers. I fell in love with my husband when I was 16 and he was 26. Both our parents knew and gave it their blessing. I have also been a victim of abuse. The difference in how i felt ineach of these relationships is night and day. Even though I said I wanted to be in the abusive relationship, I also began having frequent panic attacks and other signs of psychological distress when I was thinking of or in contact with my abuser. That psychological distress, not age, is what law enforcement should be looking for when determining the legality of a relationship.
I think the laws for abuse need to be tightened. There needs to be a "registered domestic abuser" list for anyone who can be proven to have threatened anyone in order to get sex or a relationship, or who physically harms or emotionally manipulates their partner. Punishments for emotional, physical, and sexual abuse should be lifelong if there is evidence of it, like a VAR recording, a camera, or chat logs. If it's just the alleged abuser's word against the alleged victim, then the victim should be able to file a retraining order more easily, and the consequences for violating that order should be much harsher, like 25 to life in prison.
Meanwhile, the age of consent should be dramatically lowered, perhaps to 14 like it is in Japan, or maybe 15. The concept of "child sexual abuse" in regards to a teenager should be done away with altogether, and the moral and legal line should be based only on consent. Basically, the law should be based much more on whether the younger party feels safe, happy, and mentally okay with the relationship, and much less on an arbitrary number.