“Garbage collection” is ambiguous, actually; reference counting is traditionally considered a kind of “garbage collection”. The type you’re thinking of is called “tracing garbage collection,” but the term “garbage collection” is often used to specifically mean “tracing garbage collection.”
That’s fair; Python, Swift, and most Lisps all use or have previously used reference-counting. But the quoted sentence isn’t wrong, since it said no “garbage collection pauses” rather than “garbage collection.”