YY to TaraCarter. Of course it's about perception. Many people have a sort of sound bite/snapshot/stereotypical view of a city that doesn't necessarily match up to the reality or by definition can't do justice to its complexity. E.g. Paris = romance, city of lovers, surly waiters. Rome = architecture, piazza cafes, pickpockets. Newcastle = drunken stag & hen parties. Amsterdam = weed & the red light district. Just because you (generic you) always had fabulous service when you ate in Paris on your hen party, never had your pocket picked in Rome when you were there for the football, spend all your time in Newcastle at the Sage and the Theatre Royal and practically live in Amsterdam's Museum of Cheese doesn't change that perception for other people, or mean there's not a grain of truth in the stereotype.
So it's hardly surprising that for some, "stag do in Amsterdam" makes their mind flash immediately to "weed and red light district". Especially as it's entirely possible that the stag or the organiser has made the same mental leap. Of course there is sex available pretty much everywhere, but most cities/towns/villages don't make a tourist attraction out of it and have it included on their city sightseeing bus tours. You have to seek it out or make more of an effort to find it. I was in Amsterdam last year and on the hop-on/hop-off bus, one of the stops was described as "this stop for X, Y, the red light district and Z".
I also find there is a kind of collective cognitive dissonance here between the numbers of women who always appear on stag party threads with the "my DH hates strip clubs / would never have a lap dance / respects women too much" comments, and those who appear on the Relationships board following a break up in which porn use, or sleeping with prostitutes, or frequenting strip clubs, or serial cheating is a factor. It's one thing to trust your partner until they prove untrustworthy. It's another to make such bold statements about their true views on the sex industry when both the sheer number of male "punters" and the possible consequences for a man who 'fessed up to his partner that he enjoys strip clubs or is curious or would go along for a laugh/not to be the party pooper suggest that a proportion of the first group of "my partner never would..." women's SOs has to be lying.
But as the OP hasn't returned, the original point is probably moot.