The model reacted to the backlash from last week in a lengthy statement posted on social media Monday ... saying she had no clue the 1972 Munich Olympics included a famous tragedy where 11 Israeli athletes were taken hostage and murdered by Palestinian terrorists.

Bella explains she had no knowledge of the historical connection between the '72 Olympics and the Adidas shoe, adding ... "I am shocked, I am upset, and I am disappointed in the lack of sensitivity that went into this campaign."

What's more, Bella says she never would have participated in the ad campaign if she had known about the Munich Massacre ... and she says her team or Adidas should have known. She admits ... she should have done her own research too.

Bella adds ... "While everyone's intentions were to make something positive, and bring people together through art, the collective lack of understanding from all parties undermined the process."

As you know ... Adidas caught a ton of heat for using Bella as the face of the retro sneaker ... with the American Jewish Committee saying the shoe giant made an "egregious error" by picking "a vocal anti-Israel model to recall this dark Olympics."

Bella says she doesn't believe in hate in any form, including antisemitism, and adds ... "Palestine is not synonymous with terrorism and this campaign unintentionally highlighted an event that does not represent who we are."