Showing the flag in Belfast

This came out of a conversation this evening:

1. How I know what's going on in Belfast isn't "rioting for the sake of rioting" as in Birmingham, etc, awhile back: If it were, the Catholics would be doing it too.
2. How I know the rioters aren't Catholic: They're waving Union Jacks and singing some song I don't recognize as they pass a "Nationalist area".

  Also noted: They all look like kids. But then I'm getting old.