They are just saying that because, if they make a bad doctrine, and get too embarrassed by it, they can just make another (usually even worse) one and call the first one out of date. Then it gets relegated to the rubbish bin, never to be heard about again--and the witlesses think that, since it is "out of date", their bad predictions don't count.
And yes, I think the pious-sneer "school(??)", like all their other "schools(??)", are a complete waste of time. In the same time it takes to learn to pious-sneer, I could learn the basics of building you a brand new computer or refurbishing your not Y2K compliant piece of crap computer so it will run Windows 7 (or 8) perfectly. And that's nothing--in the time it takes to waste on the Value Destroyer Training School, I could learn to fix your computer so it runs perfectly (or conclusively discern that it cannot be fixed without replacing 90% of the hardware or re-installing the OS). The money you waste (you pay your own way) would be enough to get the courses needed to learn this, plus the tools needed to properly get into your computer to make these upgrades. And, the time it takes to "put into practice" what you learn in these "schools(??)" could be used to put a business plan together.
Now, I wonder which most worldly people would prefer--learning "the truth" and wasting all their time chasing after wind, or getting that old Windows 95 machine upgraded so they can now run Windows 8, IE10, Microsoft Office 2012, Rhapsody, Real Player, iTunes, and several other programs they themselves choose so they can do something worthwhile with it. Or, their teenagers who are struggling through school--would they rather learn "the truth" and waste their lives, or get their hard drive fixed and Windows 7 installed properly on their computers?
At least Microsoft is upfront when their products go out of date. You don't hear them getting huffy about the faults of Windows 3.0 or Windows 95. Rather, they push forward--even though they messed up on Vista, it seems Windows 7 fixed what was wrong (from positive reviews about Windows 7 versus Vista). Which is better than what the Washtowel does--claiming that everything is out of date so they can hide their mistakes instead of fixing them.