My kid talked to a therapist a few times for some minor anger issues, and he's already talking about getting him diagnosed for ADHD. He's the top student in his class, can focus for hours building anything he wants, is outgoing, and gets along with all his friends. He just has a few emotional outbursts at home, which don't affect his functionality or happiness.

So...your child is exhibiting symptoms of being high-functioning ADHD, according to their therapist?...

I don't understand the point of a diagnosis. It feels like a label would just follow him around and box him in, so we decided not to pursue.

The point of a diagnosis is to allow them to get help with things that are challenging for people with ADHD. It's not something that is going to do them any harm or cause them to be discriminated against, contrary, if it is a correct diagnosis, it can be of great help. I did but get an official diagnosis until I was in my 30s and had a very similar experience in childhood, with my parents but moving forward with diagnosis. Not having access to resources when I was younger caused measurable harm and issues that I could have otherwise avoided.

"He's the top student in his class"

With studying, or without?

In my experience, being top of the class without working for it is a great way to wind up crashing and burning as soon as one gets to college and suddenly isn't the smartest in the room

Please, diagnose your kid even if you think he doesn't have ADHD

He's the top student in his class oh no. He's gifted? Get ready for potential burn out in teen years or college years. These problems can change over time, and its impossible to predict how these conditions will play out, but I'd like to warn a parent your kid might need special attention / support considerations apart from a neurotypical child.