He just said this today.....
There have literally been studies which show exactly this damaging effect - articles do get written differently, and the number of articles on certain topics is affected, because of Wikipedia's gender problem.Another fallacy is that the gender imbalance necessarily creates a content bias. Would having more female editors have affected the articles on prominent women such as Queen Victoria or Hillary Clinton? Would it increase the number of articles on female professors?
Now, Poetlister does have a tendency to run his mouth off and speak authoratively about things he clearly hasn't researched, things which are easily debunked (which sends him into coward mode, and sees the staff rush to protect him).
However, what I think is more likely here, given he must be aware of those studies, is that he knows fine well what he just said is wrong, but he is only saying it to troll people who disagree.
Wikipediocracy has a very poor record of retaining members who do know what they're talking about re. the gender gap, and conversely, they have a bad habit or retaining and even encouraging those Wikipediots who believe things like this are indeed fallacies.
Why does he do it? Who knows. Perhaps he's bored. Perhaps he just loves provoking people. Perhaps there's something deeper here, given his past of pretending to be women.