There are two kinds of workaholics - the ones who enjoy work and those who suffer from their work.
The article hits on the first kind in the passing
>> Of course, to work hard, it really helps if you enjoy your work.
Working hard when you enjoy your work is easier and might look like workaholism to someone who is definitely not. If work is play, you might play longer & that gets a lot done, because mistakes you throw away don't feel like wasted time.
The workaholic that people knock are the ones who work because it gives them positive feedback they lack in the rest of their lives - from an inattentive parent, disrespectful spouse or demanding children.
My work environment is extremely gamified and well designed to give me great feedback to improve, excellent rewards for performance and throw in some respect of my peers. The home life is Sisyphean in comparison - cook dinner today and it doesn't lie on a progression towards cooking less tomorrow.
It's easy to get sucked into that and work on a death-march, because it feels like progress on a daily basis. That "How we built Internet Explorer" tweet felt very familiar to me, because I would definitely get sucked into a mission like that.