It was a personal argument but it was aimed at a lack of perspective, and not knowing what he doesn't know (a chronic failing of youth, and I'm young myself), rather than an attempt to insult him for it's own sake. As you're hinting at, rather than being upset at me calling him 'some kid', maybe he should wonder why his age is so easy to peg.

He didn't seem to grasp why working with streams of bytes is important in this context, and why extremely spotty/inconsistent support for it is not sufficient. If he had a broader base of experience, or if he was inclined to listen to those who have such experience, maybe he'd get it.