The big companies don't want you to think about this because they benefit from being able to hoover up everything with a couple of clicks. There's nothing wrong with having to show up in person at a courthouse to see arrest records.
Making a human have to physically show up to make a request for a record does a nice job of adding just enough friction that you can't create these abusable repositories quite so easily.
If the point is to let everybody know so the arrestee’s friends can know and possibly help, making the records harder to find doesn’t help.
That doesn’t mean mugshots need be online, but in today’s photo-centric world it’s not clear a textual posting would be adequate for the problem.
So no, I don't think that is the point, per se. But I think they do make it more likely that someone will say, "hey, DiggyJohnson, isn't that your uncle Fred?" If you're in a revolutionary or criminal group you might scan the arrest records in text, but if you don't have a specific reason, you're unlikely to but might recognise a photo.
Trying to control the information by saying it's freely redistributable but you have to go down to the courthouse doesn't work - the surveillance industry just pays someone to go to the courthouse and retrieve the records however often is necessary. In fact putting up such a barrier actually helps them, as now other people looking for that data are inclined to just pay a surveillance company.
What's needed are regulations preventing companies from amassing and trading in personal information, regardless of how and where it is available. There still may be lone individuals who create their own repositories of records (ala free speech), but stomping out the commercial motive for surveillance would eliminate the sheer majority of the activity and preclude it from being a cornerstone of societal control.
Arrest records are a bit different as you need to balance the rights of a person against the benefits to society.
A person should not be punished simply by having an arrest record--that violates "presumption of innocence". Blind promulgation and aggregation of such records violates lots of people's rights. The police arrest people for shitty reasons all the time and then never press charges.
If you want to promulgate an individual's arrest record, you should have to have some reason that overrides the right to "presumption of innocence" if you want to promulgate or aggregate that record. And you should have to show up with a piece of paper in person to get that record.