The commandment forbids bearing false witness against our neighhbor. Most especially, that would be making false statements about him which would tend to harm him.
It would seem conversely to require speaking the truth.
So ...
If we see a brother engaged in sin ... and we praise him for it ... call it good ...
It seems to me that we're speaking falsely about him, and (by encouraging him to continue in his sin) bringing harm to him.
Seems to me that meets the criteria for "false witness".
Conversely, bringing his sin to his attention and calling him to repent would be speaking the truth about him, and doing so to prevent further harm coming to him.
So it seems to me that even the 10 Commandments require or at least condone judging another person's behavior.
Thoughts?
I think you are over thinking it, it really isn’t that complicated.
False Witness is simply saying something that you know to be untrue about another.