I agree the parents haven't been formally arrested and there isn't a cogent case yet (DNA traces doesn't quite equal fingerprints, and since there was apparently just two rental cars in that place, it's comnceivable that a killer/abductor could have used it before the McCann couple did - though I can't see a local criminal would be transporting a live or dead Madeline in a rental car while every cop in the country and thousands of others are looking for the girl)

Anyway, honestly I'm less cross with them than with the media who have blown the story out of any proportion and also helped the McCanns milk the thing and capitalize on it. The couple have been helping to sell newspaper copies all over the world, or most of it.