Hugh,
Whereas I agree with your sentiments regarding sorting the wheat from the chaff in NOTAMs, this is not as silly as it it might at first appear. Not every military airfield has an AEF. AEFs do not fly every day. Most pilots do not know where the AEFs are based. So, when you're planning a cross country flight and checking the NOTAMs, this information is actually quite a relevant and convenient means of familiarising yourself with a military airfield, near your intended route, that has AEF flying going on and is active that day. I know airfields are where aircraft fly from and around and some have more movements than others but increased aerial activity IS of interest to airmen (and airchix) and forewarned is forearmed.
The actual design of the NOTAM system, however, is clumsy and not that intuitive but that is a subject for another thread.
Cheers,
Pontius. Ex-AEF pilot