And that sounds like what the author of the OP said here:
"I’m willing to bet, at some nebulous point in the future, long after Drexler and I are dead, someone may eventually develop a technology sort of vaguely like what he imagines."
It's been a while since I read Drexler's books, but if I remember correctly he alluded to more mechanical processes than biological ones. The article you linked to is purely biology and not really what Drexler was arguing for.
No, it's not purely biology. It is using biological elements to synthesize artificial constructs with exact mechanical dimensions.
By analogy, when a carpenter takes a tree and cuts the tree into boards that's engineering, not biology even if the raw materials were provided by biology.
And when you then use those boards to build a house, that's engineering too.
