Referee Lee Mason took no action when Rooney swore into a television camera while celebrating a hat-trick in last week's 4-2 win at West Ham United but local media reported he later said he would have sent him off had he seen the incident.
That admission came before the Football Association (FA) imposed the ban which rules Rooney out of Saturday's Premier League match at home to Fulham and next weekend's FA Cup semi-final against Manchester City at Wembley.
"I think he (Mason) was put under pressure... it's hard to imagine a referee would send a player off for scoring a hat-trick," Ferguson, whose relationship with the FA is already strained, told a news conference.
"But he did put himself in the spotlight and if he doesn't send the player off for swearing the question will be has he got double standards?
"It's a very difficult position for the lad to be in, I feel for him, I really do. I don't know how his career is going to go now. But I think he was put under pressure."
Ferguson is currently serving a five-match touchline ban handed to him by English football's governing body after a misconduct charge.
In the FA's bad books for comments he made about referees, the Scot also criticised a policeman who suggested that had Rooney acted like he did in a public place he would have been arrested.
"I have seen a thousand Rooneys. I'm sure most police officers have. The same aggressive stance, bulging eyes, foul-mouthed rant, fists clenched, surrounded by his mates, all cheering him on," Superintendent Mark Payne wrote on his blog.
Ferguson dismissed that as simply a case of someone trying to draw attention to himself.
"There is an issue in the modern world, the need to be noticed. There's a wee guy sat in the Midlands who has probably never been recognised in his life, managed to elevate himself to whatever he is in the police force," he said.
"Have you ever seen Birmingham on a Saturday night? Do police actually arrest people for swearing on a Saturday night? Deary me. That's a good one isn't it."
Rooney, who apologised for his foul-mouthed outburst, lost an appeal on Thursday against his ban and Ferguson questioned whether the England international had been fairly treated.
"I don't know if you can use that word 'fair' any longer. We put an appeal in and the lad wrote his apologies for swearing. But I don't think we expected to get a result to be honest with you," he said.
"We're disappointed but we'll have to get on with it and we'll be united with it... we've got a good squad and players have been showing fantastic determination. We're going to be hard to beat, that's for sure."
United could go 10 points clear at the top with victory on Saturday as second-placed Arsenal, who dropped points last weekend in a 0-0 draw with Blackburn Rovers, do not play until Sunday when they travel to Blackpool.
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