Discernment vs. judgement in the labeling meditation

To watch the mind, as far as I understand, is to simply watch the mind without judging it. But there is a method, which teaches us to note sad when we are sad, dislike when we dislike something, happy when we are happy, etc.. How is this mental labeling different to judgemental mind? Will this indirectly train someone's mind, to become more judgemental of oneself and others?