I'd suggest popping down to the local library, Jon, they should have a copy of the Spectator.

Grief comes in many forms and degrees. It happens when something gets through to us, so we feel it personally, and it can happen in all kinds of circumstances, typically when for some reason we feel some commonality with the other person.

In fact there always is an enormous commonality with any suffering person, but in order to survive we maintain barriers against recognising at an emotional level. Sometimes those barriers break down, and sometimes that happens collectively. There's nothing artificial or shameworthy about that.

And it's also true that it's possible for this to be exploited in various ways - just as this can also happen sometimes even within grieving families. People can fake it, and people can milk it. But the suggestion that we can't be truly overcome by grief for people we never knew just isn't true.

There's a sense that when we grieve, at some level our grief always reflects a sharpened awareness of our own mortality, and the mortality of everything around us:

Margaret, are you grieving
Over Goldengrove unleaving?
Leaves, like the things of man, you
With your fresh thoughts care for, can you?
Ah! as the heart grows older
It will come to such sights colder
By and by, nor spare a sigh
Though worlds of wanwood leafmeal lie;
And yet you will weep and know why.
Now no matter, child, the name:
Sorrow's springs are the same.
Nor mouth had, no nor mind, expressed
What heart heard of, ghost guessed:
It is the blight man was born for,
It is Margaret you mourn for.

(Gerard Manley Hopkins)