Mexico not called a democratic country because of following reasons -:
1. since its independence in 1930, mexico hold elections after every 6 years. country has never been under dictatorship or millitary rule. But until 2000 every election was won by party called PRI.
2. PRI was known to use many dirty tricks to win elections.teachers , parents , employes and workers in government offices were forced to vote for PRI.
3. It all mean that, mexico had not free and fair elections where those who currently in power have a fair chance in loosing.so, it is not a democratic country.