Not crazy at all, cth. Think about it - what does "close to their due dates" mean, really?
When I tested positive at 39 weeks it was explained to me that I may or may not still be positive at 40 weeks, and it was my choice whether to take the antibiotics or not (I did, but it did add another complicating factor in an already long and difficult labour).
So many people go overdue, others deliver early - getting a test done near the point of birth would be nigh on impossible to predict. Thus meaning lots of missed tests (and therefore missed gp appts) for those who deliver early, and perhaps pointless tests for those who go overdue. All at a huge cost to the nhs.
Around a quarter of women carry GBS at any one time. It's normal. But obviously a quarter of babies do not suffer problems. Research shows only a very small percentage of babies born to women with GBS go on to develop GBS infection. Meaning that, if everyone was tested, thousands upon thousands of women would be having pointless IV antibiotics during labour, which would affect their birth choices.
Antibiotics in labour were a big deal for me. As my labour was so long I had to have four or five lots (can't quite remember!) which obviously affected the active water birth I had planned.
I'm not anti-GBS testing, per se. I'm just pointing out that it's not as simplistic as saying not testing for it is "crazy." There are very good reasons why the test isn't offered as standard.