The extra-cynical might even say that taking down sites like this contributes to a power imbalance between police and sex workers which too many police officers take advantage of:

https://www.mercurynews.com/2016/07/02/oakland-police-scanda...

https://babe.net/2017/07/11/perfectly-legal-cops-trick-prost...

https://en.wikipedia.org/wiki/Police_abuse_of_sex_workers_in...

I am not quite cynical enough to think that law enforcement pursues these sites for the purposes of maintaining that imbalance. There are many different attitudes towards sex work (and everything else) among law enforcement officers, and many of them probably really do believe they're doing it to keep kids safe.