I think there is some confusion about used terminology, where legalization is more like 'regulation', while many european countries do not criminalize prostitution but do not have legal framework for prostitution (e.g. 'abolitionism' in the Wikipedia link). In these countries prostitution is perfectly legal (but not necessary 3rd party involvement, which may may be used to bully prostitutes by attacking their business partners, e.g. landlords renting flats).