The show's judge, who is mentoring the groups this year, saw two of his acts - Bad Lashes and Girlband - ending up in the bottom two in the first live show. Bad Lashes were eventually voted off, giving Girlband another chance to impress the public next week.
Speaking about the history of X Factor girlbands, Walsh claimed: "Girls don't like voting for girls. They generally don't do well in these competitions, let's be quite honest about it, you know?"
However, Louis insisted that his groups did not deserve to be in the bottom two, complaining: "They were singing and dancing as well, some of the other acts were just standing there and singing."
Meanwhile, Bad Lashes promised to stick together despite their early exit. Band member Sam Bennett, 21, vowed: "It's not the end."
The X Factor continues next Saturday at 7.25pm on ITV1.