Nobody's attention deficit / hyperactivity disorder.

But lots of people are attention deficit / hyperactivity disordered. Or for short, lots of people are ADHD.

They just used a different D than you expected.

Well, for a lot of neurodivergent people it's actually a part of who we are, not a condition we have, so even though you might not like it doesn't mean it's wrong. Personally I hate people telling me that I have autism and ADHD. I am both those things.

This article explains it quite well and even though it's about autistic people it goes for ADHD people as well.

Eh. When people say this they mean

My son is [of medical status] ADHD.

It's like how people say "the car needs washed". They dont say [to be] anymore. It enrages me, but I've been coached that language evolves and we apparently need to respect that.

I personally think it's dumb, and people. Should be held to account: your child has a condition, they aren't a condition.

More trivially but also annoying: your car has a condition, it isn't dirty.