I'd say that's a load of bullshit. I don't think lack of social skills is a problem for hikikomoris because they detach themselves from the real world. I say it's a problem because they treat the internet world differently from the real world.
Take me for example. I can go out at any time and hold a fluid conversation with just about anyone else. Granted, the experience would piss me off to no end because I heavily dislike everyone else, but let's ignore that for a second. The reason people can't interact socially after spending time on the internet is because the internet is the only place they can be themselves. In the real world, If you try to take your sense of humor used on forums or imageboards (Like my deadpanning, my brand of humor, for instance), it would be a very awkward experience. After finishing a joke, you'd have to wait for approval in the form of laughter from your peers. That can be an extremely intimidating experience, and it would take a lot of mental fortitude to move on if no one understands your joke or laughs.
The internet is a security blanket for a lot of people. They can be themselves with no fear of being mocked or laughed at, because at the end of the day, it doesn't matter. Being a hikikomori isn't necessarily a bad thing. The bad thing is convincing yourself that real life isn't safe enough to be yourself.
Stop doing that.