What a picture.
One of the problems is that the left in Mexico has focused heavily on indigenous peoples for some time now. This is actually one of the things that has led to their dropping even further back, because during the 1970s there was even leftist opposition to teaching them Spanish ("destroying their culture," etc.). Many indigenous Mexicans live in remote areas and still do not speak or read and write Spanish, or at any rate, don't do so very well.
Interestingly enough, when the "indigenas" come to the US, they seem to manage to learn English. It may be bus-boy English, but it's enough to get by, and they do well enough to go back to their villages with what seems to them like a dazzling amount of money.
But the left has always been heavily invested in separating out vulnerable groups and keeping the poor poor. It gives them power, and they have a lot of power over these barely literate folk from the south.
You said it. The stock in trade for the left is catering to the poor ... leveling society down to its lowest common denominator.
The towns and rural areas in Mexico are charming and wonderful ... time out of time. But the government's fix for indigenous people was to teach them how to market their crafts to sell to tourists. For many this is their only source of income ... not a good way to get ahead in life and join the middle class.