Half the article was them complaining about poor working memory, and the rest about getting stimulation/dopamine from unhealthy sources.
Everyone has "a little ADHD". We all occasionally, forget things, hyperfocus on things we are excited about, etc. ADHD is the disorder of having those struggles so often it's debilitating. It stems from having an underdeveloped frontal lobe that doesn't feel dopamine as well as neurotypical brains do, meaning an ADHD brain needs more stimulus to feel healthy.
Because of the deficit in stimulus, people with untreated ADHD are statistically much more likely to have a substance abuse disorder (SAD); but in many cases, treating their ADHD (with medication and cognitive behavioral therapy) has the side effect of treating their SAD.
Addiction, in the public consciousness/vernacular, is more abstract than SAD: it can mean anything from chemical dependence to unwanted habits. I suspect most people tend to make a false equivalence between the former and the latter. I see all the time people struggling to change a simple habit and immediately labeling themselves "addicts". I think that's a unhelpful characterization.
I think the point people tend to miss is that in order to change a habit, you don't just "stop doing it": you must replace it with an alternative dopamine source. This is especially tricky with untreated ADHD.