ACLU gets one right. They should have no more right to do this than go through your house, mail, and banking accounts.
This stuff needs to be illegal bigtime.
Having said that, I'd wonder just how effective this kind of request would be. An applicant can create multiple Facebook pages and selectively show the employer which one paints him/her in the best light, or can (as someone else pointed out) simply tell the employer that they don't have a Facebook account.
Where was the ACLU when the son of an elected Democrat hacked Sarah Palin’s yahoo email account and posted the contents online?