Because those that passed the new law equate sex trafficking = prostitution -= all private consenting adults.  
Remember prostitution is illegal in the U.S. other than the pimp houses in some counties in NV.  
We lost at the 9th Circuit for private consenting adults.  Now almost all sites have shut down since ads or "promoting" prostitution in the U.S. expose all involved with 10-40 years in prison.  This of course increases harm potential and risk which is why it was totally decriminalized in Canada based on harm reduction when its legal as in other countries (C36 not enforced in most of Canada since should also be struck down as now being challenged in London against the "safety of persons" under the Charter of Rights. But in the U.S. the massively funded groups have controlled the media that all prostitution is the abuse of women and no women would voluntarily be a sexworker unless forced into it.   This lie prevails in the U.S.

So if the federal prostitution law is supreme over the state law when a conflict occurs, then the Nevada prostitution ripoff joints would be illegal under federal law.  Sort of like how marijuana is illegal under federal law notwithstanding the state medical marijuana license.  

So som f's signed a silly piece of paper Dave, aren't you caravaning soon back to Canada