Further explanation ...
On the men's side, to generalize, the lower D1 conferences play their conferences tournaments the first weekend, then the majors (like the BT) play the second weekend, followed by Selection Sunday.
The women, so they don't bump up against the men, reverse their schedules, and the major women's conferences (again to generalize) play their tournaments the first weekend, and now more of the lower D1 conferences are playing this weekend, with Selection MONDAY to follow.
The women's NCAA Tournament starts two days after the men's ... on Sat/Sun March 21/22