Whoever wrote that piece has apparently never read Article IV, Section 3 of the Constitution. That lays out how new states are admitted.
Unless I missed it Art 4 Sec 3 just says Congress decides
https://duckduckgo.com/?q=Article+IV%2C+Section+3+of+the+Constitution.&t=iphone&ia=web
If that implication is simple majority then we are well and truly _____ed.
The article I linked said 60 votes needed in the Senate.
Please feel free to quote otherwise