In all honesty...who cares? You can whip every idiot and detractor you meet, and at the end of the day you'll have bloody knuckles and the world will still be full of idiots.
I came from a smaller town, and was top in my high school. I had numerous scholarships and plenty of paths to take. Sure, people poo-poo'ed my choice and even denegrated it. Other parents "took pity" (while looking down their noses) at mine for my choice.
The best answer is a life well-lived. As a cadet at USMA, I had experiences that my peers at State U, Bible State Jesus College, and Stereotypical Liberal Arts College & Music Conservatory could only dream about. As an officer, those opportunities have only increased.
It's fun to go back to that little town. It's fun to see how fantastically exciting and challening my professional life has been and hear tales of the children of those same condescending parents who graduated from State U and moved home to live on said parents' couch (my mother recounts these tales with glee).
I had the chance to provide armed overwatch for a high school buddy in Iraq. He was a direct commissionee who ran route clearance missions from Baghdad to Hillah. It was great to be able to have his back while he plied a dangerous trade.
After the deployment, we met up at the small town bar our grandfathers drank at in their younger days. We swapped stories and recounted our near misses together. No one else in the bar, including all those folks who thought we were fools for ever serving, had anything to say. They just listened.
So tell your kids to live well and serve well. It's a better answer than you'll ever give those fools.