The signature was changed months ago, the fact you only have an issue with it now after you tried across multiple memorial threads to get a reaction from him says more about you.
From what I can see the context is condemning the bombings, if anybody is genuinely offended then I am sure they would say it would have said.
Just pretending to be suddenly offended because you got a reply after trying your hardest to get one is even worse. You clearly don't grasp the context of it and because you try to be clever and it backfires you have focused on that.
A couple of things:
1. If you want to bait people into giving you a reaction, don't act the victim when you get one.
2. If you don't want people to reply to you, don't try and act smart all the time or follow people about who will give it back
3. I'm not a teacher, if you want to act like you are in a play ground and throw punches or stones at people then don't whinge when they come back at you. There is so much bickering I know, but if you want to give it loads then cry about it don't expect sympathy.
You have done it with me also, tried to be sarcastic, patronising and cocky and then acted the victim when I reply.
If for example if somebody changed their Sig and it offended and somebody said "look, that's a bit offensive" as soon as they saw it then that's a different story, especially if they knew what it actually meant.