KJ is featured in the new promotional spot for her 818 Tequila on an agave farm in Jalisco, Mexico ... where her operation is running. The video and pics feature a lot of native farmers -- with Kendall alongside them rocking pig tails, as well as what some describe as traditional Mexican garb.

Online critics almost immediately chimed in, calling it cultural appropriation/tone-deafness/colonizing/exploitation ... you name it. It's all being sent her way right now.

It should, however, be noted that celebs like George Clooney, Rande Gerber, Dwayne "The Rock" Johnson, LeBron James and Kevin Hart have all launched tequila brands of their own without criticism. In fact, The Rock recently posted a video of himself with Mexican farmers very similar to the one Kendall put up.

The biggest criticism, it seems, is that Kendall is hijacking Mexican culture and trying to wear it as a costume for a photoshoot she went down there for ... and that she's being disrespectful for trying to pass as a "ranchera."

However, most critiquing Kendall just plain have it wrong, we're told the focus of the ad was to highlight the farmers doing the actual work to make the product. Kendall has created jobs, and those involved are grateful for that.

Our sources say Kendall has been very passionate about 818, putting in the work, doing the research and making sure she works with farmers to put out the best project possible.

Perhaps there's some merit to come of the criticism, but other quibbles that have surfaced are absurd ... like at least one person claiming she's modeling a "chic migrant worker look," while another person said they could "see the pain in this old man's eyes" -- referencing one of the dudes in the clip.

For starters, this took place IN Mexico ... so the migrant worker critique is BS. Also, to assume this man is being exploited/mistreated by working on the farm is about as ignorant as Kendall is allegedly being by posing with the workers.