The most important part of your letter is toward the end. You say your parents have hated every guy you’ve dated. That suggests to me that either you have terrible taste in men or perhaps your parents are having diffictulty with your transition from being their little girl to being a teen who wants to date. Of course, it could be a little of both.
Back off the immediate fight. Arguing about the merits of this boy is not the issue and fighting about it will only make things worse. Instead, gather up every bit of maturity you have and ask your parents what’s really going on that their feelings are so intense. Are they ready to have you date at all? What do they see as reasonable ground rules? Are their opinions about what and who is appropriate okay or do you think they are out of touch with usual teen relationships? Can you find places where you can agree?
Listen respectfully and with an open mind and you will gain your parents’ respect. Try to understand their desire to protect you as a way they are loving you. Tell them that. Ask them what they need to see you do to feel more confident that you can handle this next stage of life. Remind them that you are going to continue getting older and that part of getting older is trying out relationships.
Don’t fight. Negotiate. If you can pull that off, you will have already demonstrated that you are developing the maturity that is needed to manage romance.
I wish you well.