"I was shocked that Latinos and Asians and Native Americans were not a part of this conversation," says Sanchez, chairman and co-founder of the National Hispanic Foundation for the Arts, based in Washington, D.C.
"They have this idea that the paradigm is still black-white and they need to expand the conversation. That it was so narrow is indefensible."
The all-white list of acting nominees led to widespread criticism in the weeks leading up to Sunday night's show and to the hashtag movement OscarsSoWhite. Rock was praised for introducing an unusual level of candor about race to the telecast, but his comments were almost exclusively about blacks, and the show overall made only brief references to other minorities.
In one segment, three Asian children carrying briefcases walked out on stage and were introduced as PricewaterhouseCoopers accountants, an apparent reference to Asians being good at math.
"If anybody's upset about that joke, just tweet about it on your phone, which was also made by these kids," Rock said.
Mee Moua, president and executive director of the Washington-based Asian Americans Advancing Justice, said in a statement Monday that the show was a setback for diversity.
"Last night's ceremony, and particularly the 'joke' involving Asian children, which played off more than one damaging stereotype of Asians and Asian Americans, exposed one of the failings of how we talk about race in America: race relations are not a black-white binary," she said.
"It is to all of our detriment to look at race narrowly. We need to work together to dismantle the systems that devalue the experiences of minority groups so we can see the tales of the diversity that have shaped our nation reflected accurately.
A publicist for Rock, Leslie Sloane, said Monday that he was unavailable for comment. And the Academy of Motion Picture Arts and Sciences did not immediately respond to a request for comment.
Sanchez said that he watched closely to see if any attendees were wearing brown ribbons, which Eva Longoria and others had suggested as a protest against the absence of Hispanics.
"I didn't see one person wearing the brown ribbon," he said.
Some at the Oscars did make broader calls for diversity. "The Revenant" filmmaker Alejandro Gonzalez Inarritu, in his acceptance speech, urged "our generation to really liberate ourselves from all prejudice and ... make sure for once and forever that the color of the skin becomes as irrelevant as the length of our hair."