The celebration of sex in Atlas Shrugged was fairly controversial in straight-laced 1950s America. Sex is an expression of the strikers' value system, which prizes individual happiness and the uniting of the mind and body. Denying individual physical impulses is as bad as denying individual happiness.
Other characters take a very negative view of sex, treating it as shameful or tawdry. People who condemn sex are themselves condemned here, largely by Francisco and Dagny, who each give speeches defending sexuality.
This isn't to say that Galt and his strikers are advocating a sexual free-for-all. They actually promote highly discriminating sex, between people who love and/or admire each other. In other words, the mental and the physical should reflect each other. But Galt and his followers do seem to largely ignore or dismiss conventions like marriage and celibacy, which puts them at odds with society at large. Sex is not a sin in Galt's value system.
The fact that both Eddie and Hank treat Dagny like an untouchable queen reflects broader social views about sex and gender.
Sex in and of itself is not viewed positively in this book, only sex as an expression of love.