Using your example, let's say I had a 5:6 chance of winning $1 and a 1:6 of losing $100, and I guarantee a roll according to these odds.
Now imagine that you are a spectator who is asked to bet as to whether I will profit or if I will lose. Someone says, "Hey, I'll bet $50 that he (i.e. me) loses." You have a spare $50 in your pocket. Do you take the bet?
Of course you would, so the point holds. Though, as you point out, the odds of profiting alone might not be the only thing you want to take into account...
...what is your point? That if you have an 83.3% chance of winning that you'll win more often than you lose? I don't think anyone is arguing that point, as it is fairly obvious. What people are telling you if that how OFTEN you win doesn't matter. What matters is the odds you are getting/laying and what your equity is in these bets.
The point is that profit is profit regardless. Dooglus's example is an extreme case highlighting how the amount you stand to profit or lose is a secondary factor that must be considered. The greater the discrepancy of payout in relation to the odds, the greater this factor needs to be taken into account. But, if your starting pot allows you to use the Martingale strategy such that your odds of losing everything is, for example, 2^16, it may very well be worth a few trials to some people.
You're right, this is fairly obvious, but the answer to subject question should also be fairly obvious, and we're on page 45 already.