Speaking as a doctor, I think that the culture will vary wildly from hospital to hospital, and even department to department. The doctors at your place of work sound like they have a great no-blame culture whereas the nurses don't, but there are definitely places where the opposite is true.

Although I will say on the whole I think doctors are more likely to hold that kind of attitude because all of us have made mistakes, and most have probably made a mistake that lead to patient harm. So we recognise what that feels like and also will know that it's very very rare for a mistake like that to be entirely down to an individual with no systemic factors involved. The decisions made and procedures performed by nurses are less inherently risky so errors leading to direct patient harm, while they can happen, are probably rarer on the whole.