You are still arguing against human nature.
Give yourself a scenario - you have two equal candidates:
a) background check clean, no google results
b) background check lists sealed conviction, no google results
you'll choose?
now another:
a) background check clean, no google results
b) background check lists sealed conviction, google results says he stole some cookies
you'll choose?
Probably (a) both times. Unless in scenario B you can ask about his previous cookie conviction and pay him less and/or able to fire at any time.
By denying all potential information you sow distrust between a mutually consensual relationship. Do you think more or less convicts will be hired when you can't trust background checks to get all the relevant information.
In such a world gossip will replace google. "Did you hear about mark? Oh don't hire him I heard he murdered someone over a batch of cookies!"