> Should a safe online market for sex workers exist? Perhaps.

Indeed! Online listings are associated with less violence & other exploitive harms, compared to other ways such sex work is arranged when such listings have been shut down.

>But we should be able to at least agree that the people who operate it should take their responsibility as a steward of the public safety seriously.

That's a hand-wavy, euphemistic political line like one might hear from a grandstanding Attorney-General or Senator, who really just wants to ban every kind of "safe online market for sex workers", by holding them to murky and unattainable standards.

So how, specifically, would you suggest a "safe online market for sex workers" could police their listings, other than the ways Backpage tried?

Backpage tried multiple content-based strategies for banning or discouraging advertisements for odious and exploitative practices. Terms linked to problematic practices either led to ads being blocked or bowdlerized to become less-effective. I see these as genuine ways to drive both buyers and sellers of harmful practices away from the service, by making such practices impossible (or at least much more difficult) to advertise. And yet, each of Backpage's attempts to limit bad-actors is now being portrayed as evidence of sinister intent.

Backpage isn't a law enforcement agency. It lacks the same investigative or arrest/prosecution powers of the state. Backpage had to guess what the shifting legal standards of competing jurisdictions might require of them.

The likely best policy for a listing-service, if police & politicians wouldn't crucify them for it, would be to allow all kinds of ads, but also give local enforcement agencies the most-advanced kinds of notifications and "standing searches" that any of the service's power-users or customer-support personnel have.

Then, the actually legally-empowered experts – police – could do their job, and catch & punish the worst criminals, who have conveniently described exactly their crimes in public ads with contact information! That is, the police would not just scatter criminals to other channels with half-measures while prosecuting tangentially-related middlemen.

> Backpage did did at least as much to set back the cause of safeguarding sex workers than any misguided lawmaker.

Both actual sex workers & studies of the effects of Backpage-like ad-boards disagree with your assertion here.

"Sex workers 'devastated,' look to alternatives after Backpage closure": https://www.azcentral.com/story/news/local/arizona-investiga...

Both sex worker advocates & police report increased trafficking & abuse in San Francisco after Backpage shutdown: https://www.sfchronicle.com/crime/article/The-Scanner-Sex-wo...

"'People are going to die': Sex workers devastated after Backpage shutdown" : https://www.newsweek.com/people-are-going-die-sex-workers-de...

"7 Sex Workers on What It Means to Lose Backpage": https://www.thecut.com/2018/04/7-sex-workers-on-what-it-mean...

Craigslist's similar-to-Backpage "erotic services" listings, which Craigslist was pressured into discontinuing in 2010, had measurably reduced female homicide rates wherever introduced: http://scunning.com/craigslist110.pdf