Perhaps you might prefer open debate or critique, but I think most people would prefer that negative speech not occur in public. I think even politely negotiated debates can end up looking embarrassing if other people who are watching can form a justifiably negative narrative.

When people are having a discussion in a visible business setting, to some degree, the precise words being spoken by either party become less relevant than the kinds of narratives people can form about either of you. It becomes a negotiation of PR rather than a discussion of ideas.