Discerning IS judging - it is judging whether something is right or wrong, whether it lines up with the Bible or not - whether it comes from God or not.

No, I don't need to know Ruckman for 40 years, read 100 of his books, and know his birthdate and favourite ice cream flavour to be able to discern what I have read of his. I can't judge ALL of his material, but I can certainly judge what I have already read and been exposed to - and form my own conclusion on what the rest must be like based on what I have already seen and read.