You yourself may be judgemental. We all are at some points. But it's good to get in the habit of catching yourself when you make up your mind about someone, especially before trying to see their point of view.
FH: "Was it a mistake?"
Me: "I don't know."
FH: "She should probably get a good job first before she has a kid."
Me: "Sometimes life doesn't work that way, you judgmental fuckhead."
It has adopted a negative connotation as the practice of paying any unbiased attention to behavior pattern of others becomes taboo. It's only socially acceptable to acknowledge all successes and instantly forget all failures, that way no true judgement of a person's behavior pattern can be formed. If people weren't afraid to actually tell when others were incompetent, much of modern society would unfold.
B: <makes WTF-face>
A: "OMG I hate you- you so judgmental."
C: "Yeah wtf, A, learn some manners."