Foreign rugby!

So I looked up "rugby" on the WWWJDIC Japanese Dictionary and it gave me three words for rugby:

ラグビー (ragubii): "rugby"
アメラグ (ameragu): abbreviation of "american rugby"
ノーサイド (nohsaido): "no side"

It's the third one that amuses me. Is rugby really so messy that the Japanese refer to it as the game without sides? Or is it a reference to the sense of community present off the pitch between all rugby players, even those from opposing teams?

I may never know.