I was near what happened and what I could see, for what was pretty much the whole game before it kicked off, was a core of about 6 Leeds fans who seemed to spend their time yelling abuse at the Warrington fans, throwing obscene gestures and generally behaving like a group of yobs
Unfortunately, one of the Warrington fans who was egging them on decided to go and take them on, which kicked off the trouble. Three of the Leeds "fans" got ejected, with the one who'd spent the most time gesturing and being a moron was being led towards the cells
The response from the stadium staff was quick, but I do think it was sad that a few people behaved like imbeciles and, most likely, under the influence of a lot of alcohol