That the idea that there has been a terrorist attack is bullshit, so he's sarcastically letting everyone know that as a resident of Manchester he's OK because he was using his shield to protect him from this "bullshit" attack.
Cunt actually got like 20 likes. One of my mates ended up commenting because the amount of likes with no sensible response angered him, asked him why he always felt the need to be on Facebook talking this shit when these things happen and asked him what information he had a mere few hours after the event that had convinced him.Pretty restrained really.
I kind of regret not saying anything myself. But then again the guy made some sarcastic response to my mate which he then deleted almost instantly, like the coward he is. So there wouldn't have been much point.