I did say
Unless something harmful is happening
!!
All that we have to go on is what the cops have said
And I have been around too long to believe everything that they say
!
I suspect your definition of "harmful" is different to the definition used by the police and the neighbours. The cops and the neighbours don't know if the women are being trafficked or not until they investigate. It would appear that money was being exchanged in return for sexual services and there were multiple women working there, so that seems to match the description of a brothel, so they were breaking the law.
If there was one woman working there, then it wouldn't count as a brothel.
The police obviously know how these places work and that in the majority of cases the women are doing it freely without being trafficked and they turn a blind eye most of the time, but if neighbours complain then the police has no option but to act. The police can't go back to neighbours and say "yes, we know it's a brothel, but we're going to do nothing about it".
I agree that most of the time these places do no harm to others. Yes, people are making money including the women providing the services. However I guess there may be other things going on behind the scenes that are organised crime related.
I think most people wouldn't want a brothel next door and wouldn't understand what is going on and how the people that work their actually make money and they are happy doing the job. Just like most people don't understand the job of a sex worker.
If these places were in more discreet locations then most people probably wouldn't complain about them and they might accept that they do provide a useful service to a percentage of the population.