I concur, in principle, but in practice I have both seen and experienced what happens when one gets too involved. It can be quite the challenge to accept that a good idea is coming from some jerk who didn't even bother thinking about it before the meeting. Or worse, the fatal flaw gets pointed out by someone who has spent the last half hour trying to torpedo the thing by hoping to get lucky with random comments.
On the other hand, there is quite the satisfaction that comes from seeing an opponents face when you show up so well prepared -- the moment of victory is sweet :)
Um, actually you WANT the lazy jerk to contribute a good idea. For one thing, a good idea is a good idea, and the object of the game is to surface as many as possible.
More importantly, by giving the jerk copious credit, you'll do a lot to mitigate his natural tendency to derail things that may require risk and / or effort on his part. Win #2.
And of course, nothing irritates the truly motivated more than seeing a known lazy jerk score an easy victory. Chances are high that a calculated display of magnanimity from you will cause people who actually deserve credit to restore moral equilibrium by making their own (and probably better considered) contributions as well.
All that said, if you use Jefferson's approach to pre-emptivly silence a reflexive critic, yeah, it's great.
On the other hand, there is quite the satisfaction that comes from seeing an opponents face when you show up so well prepared -- the moment of victory is sweet :)