Miss Mexico Called 'Dummy' by Pageant Director, Miss Universe Contestants Walk Out

Mexico's taking a stand against the Universe ... or, at least their contestant in the Miss Universe pageant is taking a stand against the competition after an exec disrespected her.

Fátima Bosch -- Mexico's representative in the contest -- was attending a pre-pageant event in Thailand ... when executive Nawat Itsaragrisil told the group everyone needed to help promote the country in social media posts.

For some reason, Itsaragrisil singled out Bosch for allegedly refusing to take part in a beach photo shoot contestants could share on their respective accounts ... bizarrely claiming Mexico's pageant director demanded Bosch not post.

Bosch called BS on the allegation ... but, Itsaragrisil reportedly doubled down before referring to Bosch as a "dummy."

Check out the live stream ... at this point, Bosch and a myriad of other pageant contestants stormed out of the room, while others simply stood in shock.

Bosch spoke to reporters outside the event afterward ... telling them she loves Thailand and respects the people in the country a great deal -- but, added Itsaragrisil was incredibly rude and disrespectful to her.

Worth noting ... he's since released a statement apologizing for his actions -- and, Miss Universe President Raul Rocha Cantu decried Itsaragrisil's comments, and Cantu said he stands in solidarity with all the women competing in the event on November 21.