Earlier quoted context omitted.
How can you actually try to defend prostitution? Would you defend murder and rape too? Both are crimes, both are immoral, both are as old as hills.
What is inherently immoral with prostitution? Unlike murder and rape, it is a victimless crime and is in fact legal in many countries.
But since it isn't in many countries it is a haven for people trafficking, child prostitution, kidnapping, drug abuse etc. The sooner we shine a light on these darker parts of society the better everyone will be.