I've done a number races with less than 20 riders.
These are brutally aggressive everytime.

Women's races are mostly run off with very small fields, yet quite often end up being very negative.
The difference? Attitude.

Men typically would rather go down in flames, than sit around hoping for a spot in a sprint.
Women typically grew up less aggressive and prefer hanging with the pack, over taking a chance.

Doesn't make anybody right or wrong, just different ways of looking at the world.

My wife was an avg cat4 for a while and I can tell you, even she would get irritated at the lack of action sometimes. Especially when all the the womens categories raced together.