You have a kid that grew up thinking (not without a reason) that there's no better way than that do what the boss says. It will die to protect him. "Oh that kid is just a criminal, kill him!". In many cases, places where these cartels thrive are places where they locally can do better job than the government does.
I don't think that taking out the highest figure simply solves the problem. It wouldn't change much on the long run and on the short run highly increase the violence.
But more importantly, it seems extremely rare, that you could make a world a better place simply by killing somebody or a bunch of people. It's easy to think that, and a HN comment is too short to dive into that, but when you take time to think everything through, it seems far from obvious.
Your confidence that you'd sacrifice yourself heroically in circumstances it's utterly certain you'll never find yourself in is admirable.
Well not kill myself for a start...
From the standpoint of words, about "subverting the whole justice system".
So here is why this is comical to me. On the one hand, the original commenter is right. An agent who can destabilize the entire justice and legal system of a country deserve be eliminated by extreme force - at least it would be nice to see that in Mexico, a country so decimated institutionally by the drug cartels. The country has an active insurgency and is not far off from a failed state.
Where does the comedy come in? Well the other side of this coin. What is is going on in the US? There is an active agent trying to undermine the justice system and the judiciary. For different reasons, but the result can be said to be comparable. It is the very president of the united states, Donald Trump!
That is precisely what the President Of The United States Donald Trump is doing. He is actively trying to undermine the FBI, firing James Comey, bullying the Secretary General in a weird way, manipulating evidence of the Muller investigation. Trump has even gone so far as to say that he will probably do what he can to manipulate and restrain the justice department. I guess also by - by proxy - appointing someone such as Kavenaugh as a judge for the court of supreme justice.
Maybe it's not comical...It's tragicomic. I don't know. Maybe we don't even have a word for this. Reddit calls it the "Witnessing events occurring in the Darkest Timeline." I tend to agree, this must be the darkest timeline.
For more information on the creation of the justice system and the FBI, I recommend watching the movie Hoover. Although probably brief, biased and Hollywood'ised - I like the way it presents the creation of the FBI. For more information about the charades of the sitting government in the US, watch the entirety of season 04 to season 05 of Last Week Tonight with John Oliver.
These are my views. I am not american, and beyond a degree in Political Science, I probably don't know enough to make an informed statement about this. One thing is certain, we set on the other side of the pond, gasping while watching th e events unfolding each and every week of the Trump administration.