I agree, sadly. I'm not sure anyone who didn't already understand vector products is going to be helped by staring at "var rx = ay * bz - az * by; var ry = az * bx - ax * bz; var rz = ax * by - ay * bx" (as opposed to, say, [0]). Sure, it's precise and unambiguous, but it's missing the context that make it possible for a human to actually understand what it is as opposed to just calculating it (which the javascript interpreter is capable of doing fine on its own).
To say nothing of "var determinant = require('gl-mat2/determinant'); determinant(matrix)"! I guess the point is to go read the source code of the library, but I can't imagine many worse ways of learning linear algebra than reading the source code of optimized linear algebra routines.
[0] https://upload.wikimedia.org/wikipedia/commons/6/6e/Cross_pr...