That list does feel a bit "if they're from eastern Europe or Italy, they're suspicious!" Would love to know what evidence they had against each player, but I doubt it ever comes out.
After reading a lot of comment that Noah Rubin doesn't have much chance of 'making it' due to his height since his 1R win, I made a list of every man 1.80m and under (as listed on Wikipedia) to have made the 2R at this year's Australian Open. There are 15 of them.
David Goffin (1.80m, 5'' 11)
Dennis Kudla (1.80m, 5'' 11)
Omar Jasika (1.80m, 5'' 11)
Dusan Lajovic (1.80, 5'' 11)
Alexandr Dolgopolov (1.80m, 5'' 11)
Pablo Cuevas (1.80m, 5'' 11)
Kei Nishikori (1.78m, 5'' 10)
Lleyton Hewitt (1.78m, 5'' 10)
Noah Rubin (1.78m, 5'' 10)
Marco Trungelliti (1.78m, 5'' 10)
Renzo Olivo (1.78m, 5'' 10)
David Ferrer (1.75m, 5'' 9)
Dudi Sela (1.75m, 5'' 9)
Tim Smyczek (1.75m, 5'' 9)
Damir Dzumhur (1.75m, 5'' 9)
And each of the 23 woman 1.70m and under:
Daria Kasatkina (1.7m, 5'' 7)
Monica Puig (1.7m)
Timea Bacsinszky (1.7m)
Danka Kovinic (1.7m)
Saisai Zheng (1.7m)
Hsieh Su-Wei (1.69m, 5'' 6.5)
Annika Beck (1.69m)
Anastasija Sevastova (1.69m)
Monica Niculescu (1.68m, 5'' 6)
Nicole Gibbs (1.68m)
Laura Siegemund (1.68m)
Daria Gavrilova (1.66m, 5'' 5)
Lara Arruabarrena (1.66m)
Kirsten Flipkens (1.65m)
Barbora Strycova (1.64m)
Vania King (1.64m)
Yulia Putintseva (1.63m, 5'' 4)
Irina Falconi (1.63m)
Madison Brengle (1.63m)
Roberta Vinci (1.63m)
Carla Suarez Navarro (1.62m)
Lauren Davis (1.57m, 5'' 2)
Kurumi Nara (1.55m, 5'' 1)
Definitely seems like it's easier to compete in the women's game than the men's as a shorter player, but still some smaller men are managing to make a good fist of it. Gaston Gaudio remains the last men's singles Slam champion under 6 foot (Stan is listed as 6 foot exactly). Once Lleyton Hewitt retires, there won't be any active on the tour. There are no Slam singles champions under 1.70m active on the women's tour, but Marion Bartoli (1.70m) and Justine Henin (1.67m) both won within the last decade.