Rooney's comments were not broadcast by MUTV but were used in an interview on their official website ahead of Saturday's mouth-watering Premier League clash.
Soon after the interview was picked up by media outlets across the globe, United took the decision to remove it with the club concerned some might "make a big deal of it" ahead of a game that generates intense rivalry between the two sets of fans.
"He supported Everton as a kid and the rivalry between them and Liverpool is pretty ferocious now," said Ferguson.
"Since then he has come to Manchester United and he wants to win. It's nothing out of the ordinary really."
He added: "Liverpool have always been our main rival. We are the two most successful football clubs in England. When they get together you expect sparks to fly."
Rooney also said victory for United at Old Trafford on Saturday will end Liverpool's hopes of claiming the Premier League title this season.
United are currently seven points ahead of Liverpool with a game in hand.
"We're in pole position and know if we can beat Liverpool then that'll more or less end their chances of winning the league," the striker told MUTV.
United know that victory on Saturday would move them closer to their third successive Premier League title.
It would leave Liverpool 10 points adrift, with only 27 points to play for.
"They know, in coming to Old Trafford, it's going to be a difficult game for them," said Rooney.
"They also know they need the three points and I'm sure they'll be up for it - we certainly will be."
Both sides experienced European success in midweek with Liverpool thumping Real Madrid 4-0 and United edging past Inter Milan 2-0.
United, by their own admission, were out of sorts on Wednesday but centre-half Rio Ferdinand has warned Liverpool that they will be back to their best on Saturday.
The England defender also sounded a word of caution, claiming United will not celebrate winning the title until it is mathematically secured.
"They've had a good week, getting a great result against Real Madrid," he said.
"We're in for a tough game with a great atmosphere, a different entity altogether (compared to Inter), and one we can't wait for.
I couldn't care what happens to Liverpool as long as we beat them
"Could it end their title chances? Possibly, but we still have games after that to win. It's the same at this stage of the season all the time.
"People say, 'If you win this game, you win the league', but it just continues until it's mathematically over and one team wins it, and hopefully that will be us.
He added: "If we win, it will obviously make it hard for them but I couldn't care what happens to Liverpool as long as we beat them.
"If we do that and that leads to people thinking they're out of it, then so be it.
"We're there to win games, we're at home and people will be expecting us to get the three points.
"Fingers crossed we can go out there, do a good job and give a good account of ourselves."
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.