Because it undermines claims of equality? Make conferences for everyone, men and women.
And actually, don't give gold stars to people just for being women (as in, would the same person as a man receive even half the attention), this is the worst way to belittle actual achievements coming from them.
It's hard for me to understand the sense of victimhood I sometimes see from other White men.
Most conferences claim to be for everyone, but are really geared towards white cis men.
Men have been getting gold stars for women's achievements for centuries. The discovery of DNA is a perfect example.