A nuisance, an imposition but not the end of the world
Its not particularly difficult to delete your social media application before crossing the border. After all, this information is stored in the cloud so you just pull it back as needed when you get to where you're going.
I'm the first to agree that this is wrong, wrong, wrong. However, you need to know when and where to pick a fight with the Federal government; doing this at the port of entry is definitely not a good time. Play dumb, deny knowledge of anything like social media -- after all, any self respecting terrorist will be using a burner phone and sanitized social media accounts so why not just copy them?