After talking to Dogo on Neruda's Empanada/Pinochet thread. I started to wonder about sex. Mainly, I was wondering why paying for sex is seen negatively. I mean serioulsy, who readily admits to having hired the services of a prostitute?

I want you to ponder some things before answering the question.

Why do people have sex?

Sexual behavior in humans may be performed for the purposes of reproduction, the expressing of affection, spiritual transcendence, the release of tension, the experiencing and enjoyment of  pleasure (known in this context as " sexual gratification"), for physical exercise, or a combination of any or all of these things. The desire for sex is often considered one of the basic drives of human behavior.

In psychology, motivation is the driving force (desire) behind all actions of human beings, animals and lower organisms.

Motivation is often based on emotions, specifically, on the search for positive emotional experiences and the avoidance of negative ones, where positive and negative are defined by the individual brain state, not by social norms: a person may be driven to self-injury or violence because their brain is conditioned to create a positive response to these actions. Motivation is important because it is involved in the performance of all learned responses.

What other motivations are we driven by?

Fear and desire are, apparently, the more complex ones. The easiest kinds of motivation to analyse are those based upon obvious physiological needs. These include hunger, thirst, and escape from pain. 

Think about this. We pay to acquire services that will satisfy our hunger and our thirst. We pay for the right to sleep in a bed when we can't sleep in our own. In a lot of Latin American (Mexico for sure) you pay to be allowed to use a public washroom. If you are wealthy and fear for your security you pay someone to protect you. We are living in a system where we must pay/buy almost everything. So...

Why is paying for sex still frowned upon?