As a passionate rugby fan, I've noticed that some people simply call it 'rugby' instead of 'rugby union.' This usually happens because rugby union is the more popular and globally recognized form of the sport, so when people say 'rugby,' they're often referring to rugby union by default. Additionally, the other main variant of rugby, 'rugby league,' has a smaller following and is less well-known internationally. It's also worth mentioning that rugby union has a longer history, originating in the 19th century, which may contribute to its prominence. So, when people call it 'rugby,' it's likely because they're referring to the more popular and traditional rugby union.
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