Why searchable database for sex offenders but not other criminals?

Factual Questions
1

Or is there and I’m not aware of it. I know that there are background checks that one can do to determine if someone’s been convicted of a crime, but AFAIK, there is nothing like the various sex offender databases where one could find the information in an essentially public area.

Is there a reason for this, or was it just legislative fiat?

2

I believe it’s just legislative fiat. They are all various state spinoffs of “Megan’s Law”. You can google that and find the particular law in your state.