I suspect that it's a holdover from the past. There once was a time when many people had more time to read than they had stuff to read. This kind of writing was fine. Better than right-to-the-point writing, in fact, because it expanded the amount to be read without actually needing to have more to say.

Alternately, it's a way of expanding readership. If you don't know anything about molecular biology, they have to write an article at a layperson's level to explain what they mean. But if you, the reader, don't want to go through the effort of trying to understand even that, then there's this human-interest stuff that may still cause you to decide to buy their magazine.