Did these women know there were only 8 spots to be filled when they received their invitation packets? Hell yes they did. If they hesitated in signing up, for whatever reason, they're out of luck unless people have to drop. I understand the sentiment about getting women to play, but you have to draw the line somewhere simply based on logistics.
I mean, if you have a local C-tier that is capped at 90 players (18 holes X 5 players per group) and once it fills, you have 2 more women who want to sign up, do you expand the tournament somehow to get them in? Kick out a couple men to make room? How far do you bend over to accommodate them? Hell, how far do you bend over to accommodate anyone who failed to sign up before it filled?
I'll say it again: Logistics. There are only so many courses, so many hours in a day/week, and so many volunteers to staff the event. Somewhere, somehow, a limit has to be imposed due to those reasons alone. This is true for a local unsanctioned event all the way up through a major event like Worlds. You can't accommodate everyone. It is IMPOSSIBLE.
Everyone had a fair and equal chance of signing up when registration opened. It's not like things were sprung on people out of the blue. Invitations went out, registration opened on a specific date, and that's that. People that were too slow to get their registration in before the event filled are out of luck unless they are willing to patiently wait on the waiting list. I can't really comprehend how anyone could find this a foreign concept.