I hate simulation and exaggeration more than almost anyone here, but I think that Mane's actions are totally within-bounds for gamesmanship. I think the fault is with the current rule interpretation, which basically considers any contact with something resembling the shoulder or lower to automatically be handball. I think there needs to be a much wider definition of what is incidental contact, shoulders ought to be OK, a ball that would have hit your chest needs to be considered OK if it also happens to hit an arm by your side, and "natural position" needs to reflect what people's arms do when they are running or jumping. At least half of what I see called handball in the box in top-5 / UEFA competition, I'd prefer not be called.
None of which would have helped Sissoko, of course, since he stuck his arm out and left it there and got hit on it while it was extended from his body. If he's going to do that and Mane's going to aim for it (and risk the possession coming to naught if he misses), it's their own fault and credit, respectively. In terms of making a mockery of the game, it's roughly on par with the offsides trap in my mind. Oh, look, they're turning a law of the game into a tactic! Quelle horreur!