[blt]

You don't really need those calc courses to learn linear algebra. It's more about "mathematical maturity": familiarity with vectors, functions, inverse functions, a general intuition about multidimensional coordinates, and so on. A programming background would probably go a long way (although I don't speak from experience; I learned a lot of math before I started programming).

It's hard to overstate the importance of linear algebra in software. It's really worth learning.

[Steuard]

I think the calc course prerequisites have an even simpler explanation: mathematicians don't usually manage to mention the existence of vectors until the multivariable calculus class. If you're already familiar with that idea, you shouldn't need to know anything about partial derivatives and surface integrals to understand linear algebra!