Thousands of people attended a demonstration calling for a ban on prostitution in Spain on Saturday. The protesters, mostly women, marched down Madrid’s Gran Vía shopping street, with many carrying posters and placards. Some read, “We women are not commodities,” or “Prostitution is not a job.” Many chanted “stop sexual exploitation!” The protest was organized by 175 groups and drew some 7,000 people, police said. The rally came after Spain’s parliament approved a bill to tighten the criminal law on sexual offences on Thursday. As well as requiring consent from all involved in sexual acts, it a…