Alright, I'll give you my personal account of vegetarianism.

For 17 years I lived in Chile: that country next to Agentina; enclosed by mountains on one side and the sea on the other. There I met tons of people, just like anybody else who lives his life in a single place for many many years would do. Out of all the people I met there, those who were vegetarians were no more than about 3.
Now, I find myself in England. Having lived here for about 6 months and meeting just about the average amount of people that anybody meets in his fresher's year in Uni (which is, of course, less than all the people you have met so far in your life), I find myself knowing about 15 people which are vegetarian.

Now, a little bit of common knowledge: Chile, as well as Argentina, is broadly knwon for the quality of its meat.  Both countries have optimal conditions for the breeding of bovines, and therefore the final product is very good. Because of this, it is part of the culture to eat loads of meat (and very good meat).+

Too be honest, i think it has to do more with "vegetarianism" being a middle class phenomenon. there arent many vegetarians in  mexico, and mexico doesn't have great meat. i think you need  to be comfortable to a certain degree to really care about the feelings of the cow that was slaughtered for your tacos. Besides, people "nearer" to nature generally dont give a shit about animals' feelings!