This doesn't have to be a case of poor targeting by FB; it could be broadcast targeting by the advertiser who isn't as selective as we would expect.

And for brand awareness advertising, I could see that it might be worth it, depending upon the cost. I have no intention of using eHarmony (happily married here), but I'm aware of them due to both online and offline advertising. If a coworker asks me about online dating, I'm sure I'll remember eHarmony. That brand awareness has obvious value to advertisers, and if the cost is in line with their budget, it explains the "mis-targeted" ads.