The proposal does not affect RIMPAC, only the joint exercises held between South Korea and the US off the coast of North Korea. RIMPAC is a much broader exercise, and there’s been no mention of abandoning RIMPAC:
“The first RIMPAC, held in 1971, involved forces from Australia, Canada, New Zealand, the United Kingdom (UK), and the United States (US). Australia, Canada, and the US have participated in every RIMPAC since then. Other regular participants are Chile, Colombia, France, Indonesia, Japan, Malaysia, the Netherlands, Peru, Singapore, South Korea, New Zealand and Thailand.”
So don’t panic: America is not abandoning the Pacific.