There are two types of people that report staff. Haters and angels. Haters will blindly report staff with invalid or missing evidence while angels collect valid evidence in an attempt to remove the staff from power to protect the community. If a staff report has no evidence, when why should the reported staff be worried? If the report is of the staff abusing or being bias, then what protects them from demotion? Staff who have been reported will defend themselves no matter what, the moderator rank isn't something you just get.
Staff are allowed to defend themselves. It depends though what you mean by this. If you mean outside of report settings It depends, staff always have to look professional to an extent therefore fighting and public debates are not the best idea. Staff reports are not for demoting mods. They are there for the purpose of alerting mods to situations where players may feel like a mod is wrong in a decision. Some staff reports lead to demotions because staff have broken the rules too much. But it doesnt mean they were not allowed to defend themselves. If you could explain a little more what you mean that would give a little bit of context to work with.