You've got a point, and individually I wouldn't dare to question someone's gender (I barely have a grip on my own :)
All I have is the article provided. A little searching did get me to this article which details some very awful behavior though.
I guess it's more that the purpose for this entire event, to give (trans)women and non-binary people opportunities to establish a career in tech and to celebrate them, is being subverted. Space and time was limited and the extra influx of men (who clearly weren't there for the main purpose but to job hunt) put a big strain on both.
There's not much you can do about it, but that doesn't make it right.