Mexico is not 'hazardous' by the specialist meaning in aviation safety. But it does have a reduced margin of safety.
Here you get into the actual practical intent of the regulatory performance minima, and their logical basis.
Most of the minima have NO BASIS IN LOGIC. There's no special reason why we expect certain minimum climb gradiets, or stall speed ratios, or runway deviations following an engine failure. The minima have evolved as a result of operational experience and, sadly, lives lost.
The numbers we have today are based on "these numbers have worked well for the last X years", "worked well" meaning there's not a smoking hole at the end of the runway (usually). But there's no evidence or analysis to actually prove that WAT-limit plus 50lbs is "unsafe" and WAT limit minus 50lbs is "safe".
Given that the minima are, ultimately, practical and impirical values, one must then consider where the justification for the minima comes from. Essentially, it's from keeping the overall hull loss rate below 1/10^7 or so, and keeping the newspapers headline-free. Since the majority of aircraft operate below WAT limits, much of our operational experience does NOT validate the WAT limit numbers, and our impirical pool of knowledge of the effectiveness of the WAT limit philosophy is less deep than we think. It may well be that the "overweight" operations at certain airports are being drowned out in the noise of the "low eight" operations world-wide. There aren't enough engine failures at the WAT cases to compound with loading errors, airframe damage or deterioration, pilot errors, etc., to reall test the WAT limit philosophy.
Of course, as more and more airframes and engines use FLEX-type takeoffs, we are gaining more experience at the WAT limit. And we may well find out, in due course, that the WAT limits really are not stringent enough......