On Collins dictionary, one of the meanings of "sad" is: "If you describe someone as sad, you do not have any respect for them and think their behavior or ideas are ridiculous.", and it says that it is usually used before nouns in this meaning. So since it says it is usually used before nouns, is it wrong if I say like "Man... You people are sad." to some people for meaning that I despise them? Does it mean that I find them saddening instead? I think what I mean can be understood from the context. Am I right? Also, do you agree with that it is usually used before nouns instead of after nouns in this meaning?
You can see the Collins Dictionary definitions here: https://www.collinsdictionary.com/dictionary/english/sad The one I am referring to is the forth definition.