I see where you're coming from. I think Diana can understand somewhat how Booster feels. She's experienced the death or a lot of people.
But when you've just lost somebody who was very important to you the last thing you want to here is an "I understand what you're going through," speech.
And that "We were the the ones who are supposed to prevent this," thing made me want to punch something. I can't fault Diana since she offered Ted help, but Batman certainly was quite the magnificent douche.