Well, back in the day when a woman would date a man and her friend would tell her if you don't like him, don't date him. Her reply was, "a girl has to eat." Meaning, its a free meal and movie. Guys got hip to this and now dutch treat is the means for the new generation.
It has always been to purchase your girl baubles and she will do whatever you like. I know in my late teens and early twenties when I started dating, my mother warned me not to accept any sort of gifts from men. I didn't think anything about it until I got a pair of diamond earrings. I started to stutter. I figured if I made it absolutely clear that there are no strings attached and that it was just a Valentine's gift, I would be O.K. It took maybe about 6-8 months before I started hearing about this gift (over and over again) and seemed obligated every time he was strapped for cash or if I had favor with someone else, he wanted in on the discount as well. It was more irritating than an obligation and one I wish I never under took.
To answer your question directly, it has and always been insulting. I was young and it being my first diamonds was at a loss for words. I know better now and teach my children better. What could also be a deterrent,if parents bought their children these things at an appropriate age and for well established accomplishments. This way, they won't become bedazzled by wolves looking for prey.