That guy is a menace. What's next? A DNA database of people he pulls over?
This is only for criminal traffic stops, in other words, people the officer already has the discretion to haul off to jail, which would include fingerprinting anyway. The Sherriff is just making it policy to do part of what he already has legal authority to do.
If he tried to do this for civil traffic stops (speeding, rolling a stop, etc.,) I'd be yelling louder than anyone on here.