Quite a hill to die on. If I were to exhibit the same kind of pedantry you are, where a compound noun can have exactly one meaning regardless of context and specialized terms are disallowed, then I'd point out that computer != CPU so your example is irrelevant.

Folks here are genuinely trying to help. "Modern computer" clearly has a special meaning in the context of building a computer from scratch; the term is used in contrast to calculators or specialized number-crunching machines, both of which are computers and are of interest to tinkerers.

>where a compound noun can have exactly one meaning

I am not trying to assert that. In computing when setting out to design or make something "modern" that has 1 expected meaning.

>then I'd point out that computer != CPU

The book focuses on the CPU part of the computer, but the way memory, graphics, and input is done isn't modern either.

>the term is used in contrast to calculators or specialized number-crunching machines

Those have CPUs in them too and most would be more advanced than the CPU from this book.