The other factor that sets this apart is the same thing that attracted our attention to so many of the rich-guy criminals who Spitzer busted as A.G.: the dollar signs. Spitzer's alleged that $4,300 night with a prostitute is as outlandish to most of us as Dennis Kozlowski's $6,000 shower curtain.What grates is the notion that sex with a woman shouldn't be worth *that* much. I'm neither advocating for prostitution nor against it, but if the free market will support $4,300 for a night in the hay, then that is what the job is "worth" to Spitzer, and more importantly, that's what having sex with Spitzer was worth to the women who did it.
This is like arguing who is the most overpaid NBA player, but instead now it's about whether that woman's vagina is really worth all that money -- and if you can't see why that's actually insulting to all women, the point is that womens' vaginas don't have a set value anymore than anyone else's skills.
It's true that many, if not most prostitutes and call girls work for far less than that, but that isn't because the inherant value of sex work is somehow set below $100 or $500 or whatever anyone think Spitzer "should" have paid for sex.