Why isn't there legal prostitution outside of Nevada?

Basically the reason is that laws are made by elected representatives, and there are enough voters who are strongly opposed to prostitution that it would be very hard for many people favoring legalized prostitution to get elected.

As an aside, did you know that prostitution was legal in Rhode Island until 2009 when governor Donald Carcieri signed into law a bill which makes the buying and selling of sexual services a crime. Prostitution was legal in Rhode Island between 1980 and 2009 because there was no specific statute to define the act and outlaw it, although associated activities such as street solicitation, running a brothel and pimping were illegal

Please beware of the STDs before you go to prostitutes or sleep around, especially INCURABLE very common HERPES (HSV2), Every 1 out of 6 People have it, since prostitutes and girls who sleep around have sex with so many they are most likely to have it and this virus can be contracted even if you wear a condom

Search the net for herpes and you will find the details

Pls don't ruin your entire life for FEW MINUTES OF FUN, It's not worth it. Have one trusted partner for sex even it may take time to find a one

because some people aren't as knowledgeable

I don't know but btw, what's the difference between the Republican Party and a hooker? A hooker will stop screwing you when you run out of money.