Good vent. Probably everyone on this site is very familiar with the frustration involved as you illustrated above. We have all had those discussions. The words might have been different, the topics different but the attitude the same. As a matter of fact I recall reading JW literature where they were far more harsh about higher education comparing it to exposing yourself to the devil and learning worldly ways as taught in the courses which were secretly inspired by Satan etc etc.
If you ever try pushing harder when they say "I can't recall" by pulling out there own books to show them some will completely freak out on you. I was physically attacked once when I said "That's okay I have the Watchtower published book here it's right on page.....". With another Witness who was willing to refresh their memory by reading their own literature they got mad at me and accused me of producing a book which had sentences altered by Satan. In other words they couldn't even accept the teachings of their own religion (which just goes to show that some of them don't care to dig too deep). This is something that always irritated me (and does about many fundamentalists for that matter): If a JW is prepared to shun family over questioning the teachings of the Watchtower over say blood; if a JW is prepared to abduct thier children and hide them away for years from the spouse who is disfellowshipped for say smoking; if the JW is going to forego higher education; if a JW is going to tithe thier income to Watchtower and buy thier books every year and will thier estate to the Watchtower than you would think they would make sure that they are on solid ground and not just being duped by a cult with beliefs and formal lifestyle policies which change as often as someone's underwear. Some are just brainwashed and some use it as a convenient tool to control others i.e. spouse, children, extended family.