It's what I call the Garry Richardson style of interviewing, which he used to practice regularly on his Sunsay morning Sportsweek R5 Live programme.
He did it with the FA Chairman, Ian Watmore, after the Adebayor incident. Watmore is an Arsenal fan but Richardson tried to get him to be judge and jury before the FA had even received the referee's report. Watmore handled it very poorly in my opinion and instead of saying he wouldn't discuss it, effectively said Adebayor would be punished. Then on the next news & sport bulletin,the headline was "FA Chairman calls for Adebayor ban". Richardson would regularly ask provocative questions, looking to get a controversial opinion, even when his interviewee made it clear they wouldn't answer.
It's one of the firm, unwritten rules in Rugby Union that you don't criticise referees. She was just trying to stoke up a controversy and Farrell rightly refused to be drawn, when he could have landed himself in serious trouble with the RFU if he had spoken out of turn.
It's symptomatic of the decline of the BBC from an organisation that has quality and integrity at its core, to one that's little better than TalkShite. She deserved severe criticism (although not vile abuse) and if she cant deal with it she should perhaps find another career.