It's only a waste of time because the sane don't outnumber the scanners. Like he said, if everyone baited the scammers the avalanche of return mail would kill their rate of return.Why would any sane person waste their own free time on such an adventure???
The scammers use autobot programmes to send out the bait email. Let's say 1 in 1000 are silly enough these days to even start the ball rolling. 1 in ten of those might fail to sniff the rat and go all the way.
If everyone baited them back, instead of 1/10 email exchanges netting the loot it would go down to 1/10000. Wouldn't that drive any crim spare? Not knowing if any one of ten thousand emails would be the payoff. Muahahaha!
The question is really why all sane people don't bait scammers. The answer is they are poor at logic and lazy.