Former Test stars Will Carling and Jeremy Guscott were among those who criticised Farrell, singling him out after the 43-13 defeat.
England head coach Brian Ashton, though, sees Farrell as someone who could play a key role in the World Cup and has consistently backed the Saracens centre, insisting he had no hesitation recalling him for the current two-Test South Africa tour.
The 31-year-old missed England's final Six Nations appointments with France and Wales due to a back problem, but he has arrived in Johannesburg fully fit after helping Saracens secure a Guinness Premiership play-off place for the first time.
Farrell said: "I was disappointed by a few reactions after the Ireland game, which I thought were a bit harsh.
"But I knew this type of thing would happen anyway, so I was prepared for it.
"With me coming from a different sport, I think it was something people were waiting for during the last two years or so.
"It was just an easy story to write, and after watching the game over and over again, I have no complaints, albeit I was part of the reason why England were beaten convincingly by Ireland.
"Other than that, I felt some of the criticism was a bit personal, although I have been around long enough to realise that was going to come anyway.
"To be honest, I have not got too wound up about it. I think if I was inexperienced, it would have got to me, but I realise what goes on and you just get your head down and get on with it.
"I didn't read any of it or listen to any of it, but I heard what people told me.
"It is disappointing coming from people who have been at the top of the game and realise how hard it is, and they should try to find something positive or creative in their commentary or their writing.
"I don't think the performance warranted what they said, really."
Farrell faces fierce competition for the England number 12 shirt from Toby Flood, who could form part of an all-Newcastle midfield trio alongside Jonny Wilkinson and Mathew Tait when the world champions tackle South Africa in Bloemfontein next Saturday.
As overseas expeditions go, it is unquestionably an under-strength England's most demanding assignment since their so-called "tour from hell" in 1998, when they lost all seven games in Australia, New Zealand and South Africa.
Seriously weakened by the absence of players from Leicester, Wasps and Bath - plus half-a-dozen significant injuries - England are potentially on a hiding to nothing.
But Farrell added: "You always want a challenge, no matter what it is, and I definitely think this tour is a challenge.
"Hopefully, it will be a good experience for everyone who goes on it and we will come back with some positive things."