That is one interpretation of a religious view.
Well, virtually all religious people I've met have expressed the view that sex is for marriage only, and that having sex with a woman outside of marriage is wrongly "taking something" away from her. Hence the reason why the main driving force behind the Nordic model is parties like the DUP.
I have also heard the argument that it is harmful to society- that it cheapens and trivialises something which should be meaningful. In the case of prostitution it devalues and cheapens something priceless which should be freely given and shared for mutual enjoyment.
Indeed, that's another perspective on sex that I heard from countless of my religious friends back in my school days.
Oh I'm a not particularly socially conservative but hardline atheist and those arguments make sense to me.
You can be socially conservative and be a hardline atheist. Being an atheist has nothing to do with being conservative or being liberal. If those arguments "make sense" to you (meaning you agree with them and are sympathetic to them), then you should consider the possibility that you have some conservative opinions when it comes to sex.
I have very liberal views on sex. It simply does not click in my head that anyone could be harmed by two, or multiple, consenting adults having intimate contact, and I cannot see how something as simple as sex can be "cheapened" because it does not have a whole lot of meaning to begin with.