Because A2 has practically given away the farm, our dispute has been narrowed considerably. In this response, I will identify a hidden premise which lurks behind A2's case, refute that premise and his principles which ride piggy back on it, and critique a few of his subsidiary arguments.
(1) The vast majority of gambling transactions are not limited to two parties such that one's gain is equal to his counterpart's loss. When, for example, parties A, B and C all "lose" nickels in a given slot machine and Party Z wins a nickel, who "lost" the nickel? Did the nickel come from A? from B? from C? or from someone else? Or -- and this is the clincher -- did the nickel come from the casino in which case it is not even really proper to speak of it as a "loss" (since it is really a cost of doing business)? By assuming that gambling always involves a situation whereby the winner's gain is precisely equal to the loser's loss, A2 builds his case on a mistaken factual premise.
(2) Even assuming that gambling only involves a two-party transaction, A2 can only argue that the gain of one is equal to the loss of the other if he holds that economic value is something tangible (objective). The fatal flaw in A2's argument is the fact that, at this point, A2 doesn't account for intangible (subjective) values such as entertainment, and when he later does so, he refutes his own spurious notion of value. Suppose Party B was willing to part with his nickel as a "user fee" (A2's own words!) for the sheer enjoyment of it all. B's nickel, then, isn't a loss at all; it is simply the price he paid for what he gained in entertainment value. Thus, A2's own entertainment model refutes his spurious notion of value and the zero sum fallacy upon which it is based.
(3) By arguing that he need not address the fact that gambling transactions are voluntary, A2 commits two blunders. (a) He simply begs the questions he is supposed to be proving at this point (i.e. that gambling necessarily violates Biblical stewardship and fails to involve a quid pro quo). (b) He then wraps up his question begging epithets in the garb of a false analogy by claiming that the voluntary nature of gambling no more justifies gambling than a handshake justifies duelling. Though A2 may wish that gambling is as much a violation of the eighth commandment (thou shalt not steal) as duelling is a violation of the sixth commandment (thou shalt not kill), A2 has yet to prove that such is the case. In the meantime, A2's argument, like a roulette wheel, goes round and round!
(1) To the extent that gambling doesn't necessarily involve a win/loss situation (as shown above) is the extent to which we are not forced to pray for our neighbor's downfall.
(2) On A2's reasoning, a student taking a final exam which is graded "on the curve" couldn't pray for his success since, by definition, his success would entail the failure of another student in the class. A lawyer couldn't pray for a verdict since that would entail his opponent's loss. A mother couldn't pray for her son to hit a homerun to win a game since that would entail the loss of the other team. Indeed, we are commanded to pray ceaselessly, and we can pray that we succeed as long as we pray according to the will of God. This, of course, spins us right around to the question of whether Scripture permits us to gamble in the first place. Make no mistake about it: we are to pray that God's will be done. And there is nothing presumptuous about that!
(1) A2 simply asserts that money spent on gambling is spent unnecessarily and foolishly; he also shirks his burden by failing to provide definitions or guidelines for determining when a particular expense or investment is unnecessary and/or foolish. Until he does so, his argument is all bark and no bite.
(2) A2 fallaciously condemns use because of the potential for abuse (bankruptcy). Yet, on A2's reasoning, investing in real estate ventures would be intrinsically immoral since an investor who invests in risky ventures again and again would eventually bankrupt himself.
To be sure, we are commanded to be wise stewards of what God has entrusted to us, and several of my Biblical limits are designed to foster a sense of Biblical stewardship. But Biblical stewardship doesn't require us to cower in the corner of savings accounts (which, by the way, also involve a modicum of risk). Christ taught us parabolically that burying our "talents" in the ground (i.e. avoiding risk) is even more foolish than taking risk. A2 better stop digging.
Second, A2 valiantly tries to press his now-limping quid pro quo argument into service again, despite the fact that it has been beaten to a pulp above. It's time we all bade farewell to good ol' quid.
Third, A2 argues that analogies to business ventures fail to distinguish between chance (where there is no rational basis for hope) and uncertainty (where there is a rational basis for hope). A2's argument, though, misunderstands the nature of odds which exist precisely to inform us about the rationality of various speculations. Suppose, for instance, that a business man has a one in six chance to get a return on a thousand dollar investment which otherwise abides by Biblical limits; suppose further that the same businessman can place the same amount of money and get the same return on a pure game of chance such as craps by betting on "seven" which also boasts a one in six chance. Exactly how is the former based on uncertainty and the latter on chance? Johann von Goethe put A2's predicament so well when he once wrote that "[w]hen an idea is wanting, a word can always be found to take its place."
Fourth, when A2 is not inventing words to cover the holes in his case, he tries to chide me by challenging me to say upon what basis I would dissuade a young man from entering "the `field' of gambling" as a profession. Surprising as it may seem, I would not dissuade such young men. On the contrary, I would and do encourage them to become businessmen, entrepreneurs, real estate developers, etc.
While A2 may not typically find roulette wheels at church picnics, he won't typically find alcohol, dancing, or "secular" music either! What we have here -- thanks to A2 -- is a new logical fallacy: argumentum ad picnicium, which is simply a variant of the ad populum fallacy. Face it: much of the so-called Christian ethic A2 speaks of is governed more by Fundamentalist taboos than by the Word of God. That's A2's real problem. You can bet on it!