I'm saying that the casters didn't know before the interview started that Blitzchung would wear a gas mask to it.

You're saying that during the interview they encouraged him. That's true. But a caster doesn't have many other options at that point, their main job is to keep things genial and entertaining. They are not the production team, who could have cut away from the interview at any time -- even before the casters started responding. The blame goes to production.