A number of figures within football have condemned the knee-high tackle by 21-year-old McManaman during Wigan's 2-1 win at the DW Stadium two weeks ago.
Referee Mark Halsey missed the incident but McManaman was not punished retrospectively by the Football Association because one of the match officials had seen it at the time.
It was initially feared Haidara had suffered a serious injury but Newcastle have since confirmed he sustained only bad bruising and soft tissue damage, although no date has yet been set for his return to playing.
Martinez said: "I think we've been going on and on too much about it. I think it was a football incident. We lost Ryo Miyaichi a couple of weeks back and he had to go through surgery and he's out for the season. Those are incidents that happen in the game.
"I think we're taking things out of context here. I think the whole incident has been a bit of an argument about the refereeing in the game. It was a challenge with no real intent. It was an unfortunate incident that happens on a football pitch.
"I think we've been talking too much about it and it's a bit unfair on a young man to have to suffer that."
Martinez admitted that he was worried how McManaman would cope with furore over the tackle but has been pleased with the player's reaction.
"I did have concerns straight away. Anyone would," added Martinez. "All of a sudden you are the centre of a nationwide debate where you've done nothing wrong in terms of your intent. You've found yourself in that position.
"But Callum has been growing into the footballer he is now for the last four years. He's had a very good development at the club. He's been out on loan and I think he's had enough experiences to know how to cope with anything the Premier League is going to throw at him.
"But, looking at the way he's reacted in training, he's a joy of a human being and I know he'll become a stronger person after that."