Because people are going to lie in their own favor.
Do you think that claims of innocence should be given the same weight as confessions of guilt?
I don't think confessions of guilt should be given much weight either. Innocent people confess to crimes all the time.
What makes a Google search a confession?
If the implication is the Google search is an implicit confession, because in a Google search you think you are not being watched, and thus are confessing your honest desires, why would his search of love be a "claim of innocence" rather than a "confession of love"?