Search queries alone will probably tell you which way a person is leaning in an election. That by itself is not good in a democratic process hinged on secret ballot. What if the information of everyone that voted for a given candidate is collected, passed under the table to another "bad guy" in another agency, such as IRS, and then used to inflict financial harm. Yes, very far fetched, but such power is an enabler.
It seems that having courts grant warrants provides a necessary level of review by a psudo-independent body, as to sufficiently protect against undue invasion of privacy.
Based on the description in the article, I'm not sure if there are a lot of protections against personal use, like spying on a girlfriend. (When I used ChoicePoint for background investigations, it only recorded my "permissible purpose" selection, but no real validation, just an audit log of the search.)