I'm looking at Europe and I'm a bit confused how this would be a causal relationship.
9 countries have legalized prostitution: Germany, Netherlands, Austria, Switzerland, Greece, Hungary, Latvia, and Turkey.[0]
Human trafficking, in order of severity, is most linked to: Netherlands, UK, Romania, France, Germany, Bulgaria, Italy, Poland, Hungry, Portugal.
From this list alone (these tend to follow power laws) there's a higher correlation with being a Bloc State than legalized prostitution. Unsurprising to see UK and Germany here considering they are not only the most wealthy countries, but also the most populous. Netherlands... well I got no answer there but this is just a quick look.
Just given this quick look, I'd be shocked to learn that legalization of prostitution was a major causal factor in human trafficking.
I also find the data highly questionable--it's very popular to pretend that prostitution is "trafficking" with little or zero evidence. I recall a news article recently about a bunch of "trafficking" busts--that was the police putting up ads and busting the guys who showed up. Trafficking women requires that there be women in the first place and there were none.
And, no, women who move around a lot and live on-site isn't proof of trafficking--because that's also a way to make it much harder for the cops to investigate and thus a sensible safety strategy for them. I'm sure trafficking exists but I don't believe the claimed numbers at all.
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).
It’s more than 9. It’s also legal in the blue-colored countries confusingly labeled with ‘Abolitionism’. It in fact appears to be legal in most of the countries on your human trafficking list.
I don't think it is confusing and I don't think it is what you're suggesting. The wiki explicitly says that the act of prostitution is legal but the act of procuring it is illegal. Essentially you get arrested for paying for sex. The John. This is often done so that women have more of a safety net and can feel more comfortable going to police if they are abused. In other areas if you are trafficked you might feel scared to go to the police out of fear that they will arrest you.
This isn't the same as saying that prostitution is legal because the transaction is still illegal. It also doesn't resolve the issue of the correlation, which is the main point.
You can check the relevant Wikipedia pages on prostitution in e.g. Spain or the UK to see that your are misinterpreting the significance of the blue keying. It is not illegal to sell sex or to pay for sex in either of these countries (or in any of the other blue countries, as far as I’m aware).
