Thank you for posting this. I don't see anythign wrong with haggling, as long as it's done respectfully. Asking to haggle in itself isn't disrespectful, and neither is politely declining to haggle.
I've got plenty of experience haggling in my work. In my experience, haggling often leads to advantages for both parties. In a constructive dialog it is often found out that both parties have something to offer to one another.
Besides, when it comes to bigger projects, both commercial and public, there is a usually a formal bidding procedure where price and services rendered are compared for multiple providers. If you cannot be competitive, you will lose that procedure.
I realise that most of this may not be applicable to knifemaking/selling, but I humbly disagree with the notion that haggling is universally evil.