No, that can't be right. I hope you're just misremembering that, but the whole problem with patent trolls is that you can't use your own portfolio for defense.
A large patent portfolio is a good weapon against other giants in your industry: IBM, Apple, Oracle, Google, (and once upon a time) Sun. Those people basically can't sue you for violating one of their patents if you have several thousand of your own: they're bound to be in violation of at least one of yours, and it's a mutually-assured-destruction scenario.
A patent troll, on the other hand, doesn't do anything. They can sue you with relative impunity, since there's almost no chance that they're doing anything that you can use against them. The size of your own patent portfolio doesn't even enter the picture.