Some people do make everything about them. I knew someone at school and it was always "My nan's next door neighbour's cousin went to school with someone whose dog had puppies and one of those puppies went to dog obedience classes with another dog whose owner lived for a time in the same flat block as someone whose aunt worked with someone who was there..."
But I think for me, it does bring it closer to home when you look and know a place. I didn't feel particularly effected by 7/7 because we didn't go to London much and I didn't really recognise the places; they were just names to me.
We now go to London quite frequently and often do walk over the bridge and it does make me think much more deeply. It makes me imagine trying to protect the children in that situation, wonder what I'd do, how we'd react, would we have survived.
In that way we react far more to the events in London than learning about 100s of people dying in Syria due to bombing. What's that quote? "100 people dying in an earthquake is news, one child in a garden pond is tragedy". If we can imagine that it could one day be us in that situation we react much more.
For me it's an internal reaction, not something I talk about, but for some people (like my dd2) it's helpful to talk about it, to break the fear by vocalising it. It doesn't mean that they are less empathetic to the people actually caught up in it, or making it about them, in most cases.
I think it's a very human reaction to put yourself in that situation and think it could have been you. A case where it could be you is much more frightening than a case which could never be you.
And for those complaining about marking safe from people outside London. We're well outside the M25, but we still had people (including relatives) checking we were safe on 7/7. I was quite touched that people thought of us actually, even if their geography was conspicuous by its absence.