I suspect that you're underestimating how much Diane Nelson knows about comics (she was also one of the people pushing Watchmen Motion Comics, which again suggests she knows something about comics and also understands that the internet exists.)
I also suspect that you're overestimating how important a full knowledge of DC is for her job.
(Part of the problem is that there's relatively little personal information about her; for all anybody knows she's been reading comics since she was 12.)