Claiming that it should be okay to do something questionable because everyone else does it is never the right attitude. Prostitution ads should not be right next to ads for cars, even if others do it.
Those that claim how many illegal things would be better if legalized and regulated are naive.
Bowing down to socio-political pressure without being demanded to, for a service that is very clearly popular and (I believe) ought to be legal is, in my opinion, spineless.
I understand that their heart is in the right place, and I'm very understanding that their belief system may not match my own, so I applaud them for doing what they feel is right... but that is all that I can applaud them for.
No-one can possibly believe someone wants to be a prostitute.
Not only are some girls forced into it by pimps and syndicate hooking them on drugs to guarantee their "employment", even if others just enter into it out of desperation for quick cash, once you are down that path it can screw up your life forever.
So yeah, condoning it and promoting it and making it easily available on sites like CL has to be prevented for the better of society over the desire of men to have effortlessly accessible sex.
I consider that taking the high road, thinking of others before yourself. I'm under no delusion that it's going to drop even 1% with CL's listings gone, but it's still the right thing to do.