From the article:

Freedom to copy and change software is an ethical imperative because those activities are feasible for those who use software: the equipment that enables you to use the software (a computer) is also sufficient to copy and change it. Today's mobile computers are too weak to be good for this, but anyone can find a computer that's powerful enough.

You can't build and run a circuit design or a chip design in your computer. Constructing a big circuit is a lot of painstaking work, and that's once you have the circuit board. Fabricating a chip is not feasible for individuals today; only mass production can make them cheap enough.

Basically, you're legally prohibited from copying software, but you're technically prohibited from copying ICs. Hardware isn't "out of scope", it's just not the same kind of thing as software- information can be copied for basically zero marginal cost, but hardware can't.

The FSF exists to fight legal encumbrances on the copying and modification of software because the technical details of hardware and software are totally different. Although, even in that same article, the FSF advocates for and recommends free hardware designs, which are more analogous to software. You can care about more than one thing. The FSF just particularly cares about software, including firmware, being free of unnecessary legal encumbrances related to copyright.