It makes perfect sense. Girls post faster then guys. Is there more to explain? :/
You seem to be looking at one particular scenario. I will note: that scenario is very rare.
Here are some more common scenarios:
3 girls + 1 guy = Girls will statistically get +1. Realistically, they'll likely get +2.
2 girls + 1 guy = Girls will statistically get 0. Realistically, they'll either get +1 or -1.
1 girl + 0 guys = No bounds here. Realistically they'll get +10 before a guy enters.
2 girls + 0 guy = No bounds again. Realistically, they'll get +20 at least.
3 girls + 0 guys = Good lord. I don't want to know. Unstopped, they'll get at least +35.
0 girls + 1 guy = No bounds. Realistically, he'll get +12 before a girl enters.
0 girls + 2 guys = Strangely, whenever this happens, girls come in. +8 likely.
3 girls + 2 guys = Post confusion galore. Likely there will be no change.
You say cooperation like it's a bad thing. Isn't cooperation the whole point of the game, cooperation between your own side? It's happening with guys, maybe that's why you girls are complaining.
Your scenario, is, as I said, rare, and will rarely turn out the way you expect even if it did happen. And your logic of the best move being not posting is absolute, complete, rubbish. I don't know where you pulled that one out from.
The girls are disadvantaged 4 times. But guys are disadvantaged far, far, more, than that.
If you want to argue further, get your facts straight. Otherwise, play the game, and see for yourself.