Being non-judgmental is one thing, being discerning is quite another. We generally judge people and situations based on certain preferences, interests, fixed view points and opinions. It is usually something external and on the surface that makes us draw conclusions based on our mindset and biases such as colour of skin, food habits, outer behaviour, interests, job and profession, wealth and outer position etc. These things belong to the outer personality and do not give us the true understanding of the inner or the true person.
One must have discernment (a faculty that develops through yoga) to know what helps in one’s progress and what hinders. Beyond this nothing else matters. Generally the best counsel with regard to dealing with people is to be a witness full of goodwill. If someone is nasty practice equanimity and indifference. For the rest leave it to the Divine to deal with him as He Wills.