It seems that Culdians look for Evil even in Good?

Good is good wherever it manifests and calling it anything else would not alter it. Culdians are realists and recognize that those who serve cause of Evil as motivators are very subtle and camouflage their activities under cloaks of seeming Good. Also it is unfortunately true that good motivation and intent can sometimes lead to undesirable outcomes when a wider overview is taken, as witness a great deal of social legislation and social attitudes. The physician does not concern himself with the healthy parts of a body, but concentrates on those that call for attention.