Again: A and B actually have many options to accomplish the Objective -- you've just arbitrarily tossed the rest of them out by carefully constructing a single case, and then treating that case as if it were the only case there is.
In your kind example you've done it again: you're requiring that I assume at a whole host of things, none of which is strictly necessary to the objective of reaching the top of the mountain.
You have also, without justification, decided that A and B have already adopted some "assumed basic premises" which include, apparently, that A and B must choose different paths, and that A and B must of necessity reach the top all by themselves.
But with those "assumed basic premises" you've already rigged the game -- you've already tossed out the possibility that A might pay B to carry him to the top; or that B decides to drag A to the top whether or not he actually wants to go there; or any other type of behavior that will take them to the top.
It's dishonest to pretend you've done something grand, when you've really just avoided the real point of the exercise by selecting those "assumed premises" for us!
the Free Agent in question deduces as a matter of Objective Fact that he must adhere with ABSOLUTE Consistency to the appropriate Behavioral Maxim for reaching the Top of the Mountain
Here's where the "assumed premises" fail you. You've assumed that A and B choose different paths. But again, there's no reason to assume this. Indeed, A and B can't be Free Agents if they cannot choose the same path. If they're on the same path, then A and B can, midway up the mountain, decide to work out a deal whereby A carries B -- thus, your proposed Behavior is not absolute, even if it was the one adopted at the beginning of the day.
Next, you are assuming (again without justification) that both A and B are Free Agents. This is not necessary: why have you tossed out the "assumed premise" that B is not a Free Agent, but instead beholden in some manner to A? In that case, A can require B to carry him to the top on his back. Or perhaps B will have to carry A only when the latter becomes tired -- again, the your proposed Behavior is not absolute.
And in either case, there is not necessarily any transcendent moral value assigned to reaching the Top of the Mountain -- it is simply the desired objective of the Free Agent.
False. You're essentially assuming that the Objective Fact of the mountain automatically translates to the (allegedly) Objective Fact that A and B will want to climb it, which is clearly wrong. In reality, the "transcendent moral value" in the problem is whatever drives the desire for A and B to climb the mountain in the first place. People (sane ones, anyway) generally don't desire things for no reason whatsoever. The desire is based on external factors: something that transcends (i.e., is apart from) the Actors or the Mountain.
Come to think of it, this appears to be yet another example of how you've rigged the game: you've a priori decided that the top of the mountain is the goal. As a result, you have tossed out the possibility that A hates mountains, and wants to walk away from the mountain until it disappears over the horizon; or that B wouldn't notice or care whether he reached the top at all. Nope -- they've got to reach the top.
These are not idle objections -- in setting even this supposedly simple problem you have had to impose a large number of carefully selected constraints on the problem. (And you still didn't arrive at "absolutes.") In so doing, you have relieved A and B of the necessity of having to sift through the available options. You have, in effect, played the role of God.
Thus proving the Rabbi's point.