Playing too much Minecraft is considered an addiction because it has a real cost to the addict playing the game. Please note that "playing too much" is to the point that it is causing the child to do poorly in school or have other negative effects.
However, when defining addiction, I think "causing the child to do poorly in school" is a really, really dangerous standard. Several psychologists and teachers told my parents I was addicted to computers because I did poorly in high school and also spent a lot of time on the computer. Never-mind that I had worked through Cinderella, SICP, the first half of Dragon, and an undergrad crypto course in addition to a Discrete Mathemtics and Linear course by the end of high school... all while fueling my "addiction".)
I think there's a lot of danger in conflating "interferes with good grades" with "harmful". Especially in high school. Taking grades seriously in high school would have been far more harmful than my computer "addiction".
A younger friend of mine gained his first digital electronics knowledge building 8-segment displays in Minecraft, and the time spent on setting up and managing Minecraft servers gave him skills he now directly uses every day, for money and for fun.
The point is, school is bullshit (and kids smell it, they're incredibly good bullshit detectors). Pretty much anything a kid does on a computer that isn't literally browsing 9gag all day teaches them more than the same time spent doing homework. Parents need to be very careful here. School-related tasks are very inefficient way of spending time, but are easy for parents to focus on because they're quantified. You just have to look at the test scores and grades (and their first derivatives). The fact that they're totally unrelated to any education taking place is too much to think about.
So if you see your kid spends a lot of time building, creating and exploring stuff on the computer, do him/her a favour and don't mind too much if they occasionally forget about their homework. And most important of all - don't introduce insane time limits like "1 hour of computer time a day, every other day". With such strict limits, there's literally nothing a kid can do except of watching funny pictures of cats on-line or playing games. Exploration and learning takes time, and is something you don't even start if you know you are on strict deadlines (note: this also applies to adults at and after work).
I've heard this from a lot of people. It's probably the most understated advantage of online gaming among students from non-English-speaking countries.
He's been through Minecraft, done some stuff, and then fell off when it got harder than he liked. Likewise with other video games. He loved Kerbal for 45 minutes and was done. He gets hooked on video games because they are shiny, and sniffs at some of the possibilities, but then drops out. They provide enough stimulation to distract him from whatever is bothering him, and to keep him from getting so bored that he might actually read a book. But they don't provide any steps up to an actual learning threshold.
Yes, some people can learn enormous amounts from video games and such. But I worry that those people have a particular set of focus and problem-solving and follow-through skills. I don't see much in the online environment to help identify and fill those gaps for other people. Ideally schools should be able to do that, and no, too often they don't. But at least they have the opportunity to put great teachers in position to do just that.
I definitely get the possibilities of video games and I hope I'm not hung up on conventional learnings. But I fear that for a large category of kids, these games are really net negatives. I'm definitely worried about my son.
But the games are a problem as an attention sponge / stimulus hit. Thirty years ago the kid would have gotten so bored that he would have read a book or picked up a basketball or listening to music or something. Those initially would not have provided stimulus, but in time they would have, and he would have begun to associate the work done at them with stimulus and thus become more engaged with them. (I would hope. Maybe he'd start on weed, right?)
Today, it is just too easy to get a small stimulus attention hit from some game, or surfing around. God knows I struggle with it sometimes, don't most of us? For a kid who hasn't developed real engagement and follow-through, those little hits stave off boredom, sort of, but never lead to anything more rewarding.
All I'm saying is, I think the whole online environment definitely poses a new set of risks and that some people are more at risk than others.
I had some problems with following through on hard tasks in grad school. When I got to the point where Google was completely useless and I knew I had six months of work to do (at best) with very little outside guidance, I kind of got down and couldn't focus. I found that biting off small pieces that seemed either easy or interesting and then convincing myself to forget about the long-term picture until I figured out that piece was a helpful way to avoid paralysis.
Also, whispering "I could give you a hint" in your own ear is pretty amazingly helpful, for the same reason that just knowing you could just Google for the answer if you need to is helpful when you're working on a hard assignment. Less stress, I guess.
Not sure if or how that applies to your son. Also seems like the sort of thing a kid would have a very difficult time doing for themselves. In any case, it sounds like you're very in tune and thinking about things the right way. Good luck with your son.
But again, the point the author makes, and he tries to be nice about it, is that it's not Minecraft or any other games fault, it's parents using it incorrectly. Poor parenting can create bad habits, which yes can eventually become addictions. But that doesn't make the focus of the addiction the culprit, that makes the parents the culprit.