Her co-stars in the 1920s and 1930s included William Haines, Joan Crawford, Lon Chaney (Sr.), Ramon Novarro, Douglas Fairbanks Jr., Buster Keaton, Marie Dressler, Robert Montgomery, Constance Bennett, John Gilbert, Walter Huston, and Maureen O’Sullivan.
I think the implication is that she, as an adult, starred in silent films.
That there may be others still living who starred in silent films but that, younger than Anita Page, they were child stars during the Silent Era.
This explanation does seem a little off to me though. If she was born in 1910 she would have been 18 in 1928- about the dawn of talkies. As a silent film star, I think she would have had to have been a silent film child star herself.
And yes, there was porn- and I assume porn stars- in the Silent Film Era. Though from the list of co-stars, I assume Walloon isn’t offering Anita Page as an example of a porn star- unless “Keaton” is a typo.
She starred in the silent features Telling the World (1928), Our Dancing Daughters (1928), While the City Sleeps (1928), The Flying Fleet (1929), Our Modern Maidens (1929), and Speedway (1929). She played adult roles in all of them, and was 18 when she made the last three of those.