He may have created it, but he is by no means the sole reason for its success.
But he’s trying to build credibility in legitimate way. To push it forward, build that community, and make key usability decisions that massively improved things over Mac Ports, these are not things that are easily done and he absolutely deserves credit for it.
Almost all of the value of homebrew comes from the sheer comprehensiveness of the package catalog, which entirely relies on a large community of users contributing recipes. He should credit those people and not act like the appeal has anything to do with the brew cli itself as a tool.