They aren't pretentious. How daft is that.
Pointless, well, depends what you believe constitutes a 'point', doesn't it?
Are they vital? No. Will a child be damaged without one? No. But the 'point', well -
personal choice? - maybe people just bloody like it and that is fine.
tradition?
culture? - there are cultures which have very strict naming rules, which includes middle names. My husband's culture for example has a long long and vital to them tradition of honouring ancestors and demonstrating blood ties through naming. There is a set way you name. First son to father's father, second son to mother's father, first daughter to father's mother, second daughter to mother's mother, then it goes to grandparents. That sense of history and identity is very important to them. Pointless? Hardly.
At the end of the day, nobody has ever been hurt by having a middle name and it affects nobody at all, so let those who want them have them and those who don't don't and accept that your way is not the only way.
Dealbreaker. That made me laugh. I love you so much, please have my babies, I want to build a life with you, you are my everything, wait, what? You want to give our child a middle name? Begone, Devil Woman, this above all I cannot tolerate.