Why is being judged different depending on what topic one is being judged?
I was under the assumption that the question was whether being being promiscuous was being moral or not, and I stated "although it has absolutely nothing to do with them" i.e. in general that is none of your business. However, your statement now changes the question to something else entirely (please correct me, if I am wrong): is being promiscuous and not telling me/pretending it not to be moral or not (in case we were about to have sex). Now, it directly affects you, and that is a different case. Withholding such information and then leading to sex can, if I remember correctly, even be interpreted as rape i.e. gaining consent under false pretense.
Generally, I try to live by Luke 6:37: "Do not judge, and you will not be judged. Do not condemn, and you will not be condemned. Forgive, and you will be forgiven." While that does not mean anything goes with regards of behavior towards other people (as indicated in my first response), it does mean that people shall live their lives as they wish.
The problem with moral and judgement is that queer people will very quickly be at the receiving end of it.