You don't have to say you are a Sheikh to rack up sins by telling someone to “have fun in hell”
Learn the deen first before advising others.
Have fun in hell was a joke on my part. OP and I know each other. Even if I got a sin of this, the core message still stands: zina is rewarded by hellfire. Besides why dont you focus on op's post and tell him how xaraam it is, since you seem to know a lot.