I think you and fezziwig aren’t disagreeing. You’re saying as an empirical matter that lying can (and maybe often does) harm the liar. He’s just saying that it doesn’t necessarily harm the liar, and indeed it may well be that lies are often a net benefit. These are compatible claims.
Did you even read the comment I linked to? It’s whole point was about the harm you do to yourself and your cause by lying.
I think you and fezziwig aren’t disagreeing. You’re saying as an empirical matter that lying can (and maybe often does) harm the liar. He’s just saying that it doesn’t necessarily harm the liar, and indeed it may well be that lies are often a net benefit. These are compatible claims.