The Short Version
This claim is misleading. While it's true that early Artemis missions (II and III) were designed to proceed without the Lunar Gateway, NASA's own documents call Gateway "essential to the Artemis architecture" for the full campaign. Artemis's stated lunar objectives include establishing a sustained, long-term presence on the Moon — not just a single crewed landing — and Gateway is designated as central to Artemis IV and beyond. The claim cherry-picks a narrow near-term truth and presents it as applying to the entire program.