Zaha was considered one of the brightest young talents in the country when United paid Palace £15 million to sign him in January 2013 but the winger struggled to settle at Old Trafford.
The 21-year-old spent six months on loan at Cardiff earlier this year but again failed to rediscover his best form and opted to re-join Palace on loan in the summer.
“Man United was probably a bit too big really,” Warnock said.
“They haven’t got time to educate players as much as a club like Palace have.
“We bring through players like Wilfried all the time and they need educating.
“To take him as quickly as they did and with the money involved, it was very difficult I think.”
Zaha never started a game for United in the English Premier League and made just four appearances for the club in all competitions.
The winger’s displays for United were in stark contrast to the kind of form that saw him named the Football League’s Young Player of the Year in 2012.
“I spoke to Wilfried the day after I got the job at Palace,” Warnock said.
“There were four managers after him in the Premier League so there are a lot of managers who think he can do it.
“I just think he needs to be at home and to be loved – the fans love him here.”
Zaha’s attitude came into question during his barren spell at United but Warnock insists he has been impressed with the player’s character since joining the club.
“His attitude has been questioned but I know Wilfried, it’s not his attitude, it’s guidance he needs really,” Warnock said.
“He’s a bit like Victor Moses (whom Warnock managed during his first spell as Palace manager).
“Victor used to play for himself at times. I once told him he could play for his country and make a fabulous living or he could be playing for Bromley in a couple of years.
“Then we went to Cardiff one night, it was chucking it down with rain and for some reason something clicked – I’ve never seen him work as hard in his life.
“He tackled back and was just amazing – that’s why I’m disappointed he hasn’t got a regular place somewhere as well.”
Zaha’s arrival, along with club-record signing James McArthur, boosts Palace’s attacking options.
Their success under Tony Pulis last term was based on a mean defensive record but Warnock is keen for his players to play with freedom and flair, starting at home against Burnley on Saturday.
“I want us to entertain,” Warnock said.
“Obviously I want us to be difficult to break down but I don’t want to stop them from attacking.
“We’ve got a number of strong attacking players so I want us to try to get forward and create chances.
“It’s a great league and Selhurst Park is an exciting place – if we can get it buzzing it’ll be a great home for us.”