It doesn't have to be intentional, you just have to have intentionally placed your arms anywhere else but close to your sides. Players on the wall are taught to never bent their elbows and stick their hands out because instances like that can happen and do happen. She was on the outer edge by the far post, which is where most free kicks go. She bent her elbow and moved her hands away from her body and the ball hit her hand. Sometimes those aren't called but sometimes they are. That's why you always turn your head to the side and keep your arms locked. It's a natural instinct to move your arms like she did but in soccer you're taught not to do that.
AFAIK, it does actually have to be intentional (according to the rules), but having your arms out in preparation for it is usually deemed as intentionally causing it. This was about as grey area as it can get, given that the arms were extended, though in a manner in which it looked like she was going to block her face, and the kick went directly at her.
I have seen more obvious 'arms to the side' instances in professional soccer where it was still deemed 'ball to hand' and a penalty was not awarded. It almost always gets called outside the box, but is much less often called where it would result in a penalty. I don't think the handball call in itself was horrible, but I know I've seen similar plays where the call was not made. I think calling it either a clear cut call or a horrible call would be incorrect.
The free kick is another matter. When a keeper takes too much time they get a warning first. I'm not sure if there was a warning because I may have missed it, but there's almost never a free kick for time wasting going against a keeper. The referee usually lets the keeper kick the ball (after getting a warning), waits for the ball to go out of play and then gives the keeper a yellow for wasting time. I don't think I've ever seen a referee give a free kick for time wasting in that position.
I don't think I've ever seen a ref give a free kick for time wasting PERIOD. Had the handball not been a direct result of the free kick I don't think anyone would be nearly upset.