Most people who take the class are multi-classed before they take it; I think the description is simply stating that you can come at the class from either a primary spell-casting or primary fighting mentality, rather than the literal way you're reading.
That said, I'm fairly sure that the description is bioware's rather than ours, and should probably be changed at some point, to a more Layo focused description.
edit: my slow typing strikes again!