>Garbage collection generally refers to more complex systems that periodically identify and free unused objects in a less deterministic manner.

No, this is a subset of garbage collection called tracing garbage collection. "Garbage collection" absolutely includes refcounting.

There’s just no good reason to conflate the two. Rust’s Arc and C++’s std::shared_ptr do not reclaim reference cycles, so you can call it “garbage collection” if you want, but the colloquial understanding is way more useful.