In a sense you make my point for me. Interviews are sufficiently high stakes to be inherently stressful and there are always many unknowns in them. I think the interviewers very important job is to establish psychological safety in the interview even while exposing candidates to additional unknowns and difficult problems to solve. Think of it this way... Taking an adversarial approach provides headwinds, being supportive may get the whole interviewer pool further in the problems and better stimulates the supportive environment of a good office culture and environment.

Remember that candidates are interviewing with you too and you can better communicate the environment and get a better read of how they would participate when you better simulate the reality.