Off-topic: I love reading articles that use 2-column format. I think it should be done more often. Although I wished the font would have been a "seriffed" one.
In this particular case it's also not responsive, which makes it a pretty bad experience on mobile. I would be curious if there's a good version of a 2-column layout; but I don't think this is it.
Why columns? Good-length columns minimize your eye movement and make it less tiring to read.
More than about 10 words per line require you to move your eyes too much horizontally or vertically and you can lose a train of thought etc.
If you can't guarantee that, then the designer is just forcing a print convention where it doesn't belong. The solution is to make a narrower column.
Agreed. I consider Bootstrap's default breakpoints to be fairly trustworthy in the regard.
Which is not the case here. Resizing the browser keeps the same number of columns.