It was not a pure repeal of ObamaCare with nothing in its place. There were healthcare provisions. I also don’t think McCain objected to it because it was not conservative enough.
ObamaCare Replacement Act
https://www.congress.gov/bill/115th-congress/senate-bill/222
McCain objected because there wasn’t a true replacement for the amount of repeal. Remember Trump promised this would be one of his first accomplishments.