Well, try living someplace labelled '3rd world' where poverty is so bad that said Police are often paid off by companies and cartels who offer a living wage.
Those not paid off are often threatened or worse: disappear and are found months later in a shallow pit.
So no, it's not that Mexico's Federales nor National Guard nor Police 'suck' so much as poverty sucks. Poverty proliferates corruption which ultimately brings out the worst in all humanity.
Cartels taking this shit out on the people sucks. Corruption sucks. Ignorance here is also 'sucks'.