Including non-binary people was not the problem. Relevant quote:

“AnitaB.org, the nonprofit that runs the conference, said there was “an increase in participation of self-identifying males” at this year’s event. The nonprofit says it believes allyship from men is important and noted it cannot ban men from attending due to federal nondiscrimination protections in the US.”

They identified as male, not non-binary, and the event allowed men to come.