Zero is the first agnostic I see defending conventional forms of religion so fiercely. Disrespectful mockery of religion? If you really meant that, you need to lighten up a bit.
But I guess you're just pushing it to disagree with Arsenal fans.
As for the rivalries, whether you like it or not, they will always exist anywhere - come on, nobody here lives inside a bubble. No matter where you live, your local club will have some degree of rivalry with another. Or if you're the only club in town, like Newcastle is, then you'll be rivals with the club in the neighbour city (in this case, Sunderland).
Rivalry is inevitable in football. Unless there are robots in the audience.
It is not necessarily negative, but it helps fire up the atmosphere of derbies, taking them to another level, like Bobby said.
Some people will stay within the boundaries of terrace banter, others will be idiotic and violent about it. Those that go over the top are dealt with by the authorities, and that's that. I agree they're idiots, but as long as they pay the price for being so, things are under control.
I'm not about to condemn rivalries and wish they would end just because of a minority of imbeciles.
I don't believe Gerd's example would ever materialise - if both Arsenal and Tottenham would get relegated, regardless of where they finished, there would be no celebrations.
Furthermore, I think you guys got it all wrong. St. Totteringham is a "holiday" that Arsenal fans "celebrate". It is all tongue-in-cheek humour, I don't believe anyone actually celebrates that for real. This isn't something created for the Arsenal fans to celebrate. It's designed only with the purpose of winding up Spurs fans.