It's funny, because I never understood why people found Elrond attractive in the slightest until that armor. Now I totallytotallytotally get it. The funny thing is is that I've talked to some people who have felt the same way.
But okay, my theory: I thought that the Battle of Dagorlad!Elrond was really hot too, but when he gets into his robes and his everything is suddenly under all these clothes the appeal just left; SO, it is the armor. The armor makes it happen.
And since you first see him in armor from FotR, for some people it just sticks.
This concludes a study of why Elrond is a hot piece of a**.