We can infer some of it from the data in the infographic. Women are spending more time on local and civic issues, and volunteering for schools and clubs, so they may feel that these things are more important than volunteering for political parties.
Evidence of meeting #106 for Status of Women in the 42nd Parliament, 1st Session. (The original version is on Parliament’s site, as are the minutes.) The winning word was data.
A recording is available from Parliament.