While I appreciate his effort, I always felt like that page was a bit too...ideologically stamped. Later on he writes things like:

    Q: I've been cracked. Will you help me fend off 
    further attacks?

    A: No. Every time I've been asked this question 
    so far, it's been from some poor sap running Microsoft
    Windows. It is not possible to effectively secure 
    Windows systems against crack attacks; the code and
    architecture simply have too many flaws, which makes
    securing Windows like trying to bail out a boat with
    a sieve. The only reliable prevention starts with 
    switching to Linux or some other operating system that 
    is designed to at least be capable of security.

I don't think that's appropriate, or really needed. I mean sure, even my post is opinionated, but you don't see me telling someone they're an idiot because they don't understand something.

While I don't disagree with you that ESR has a strong ideological tilt, it's also useful to remember that he wrote that quite a long time ago now, when that effectively =was= true.

Going back to the subject at hand, I think that the post misses the point that being a 'hacker' isn't really about how many languages you know, it's about certain ways of thinking. The most important, IMO, things to know are all (fairly) language agnostic - algorithms and data structures. If you don't understand those and how they work and how to choose between them, then you're never going to be really good at what you do.

Also, you need to learn a functional language well enough that you can solve hard problems using it. Understanding functional programming and all the concepts it introduces (partial evaluation, currying, monads, first class functions, map/reduce to name a few) will do wonders for how you write code in other languages and will make the code you write far cleaner and more readable and easier to extend afterwards.