My experience is largely within Indian system. So my comment will be applicable to this system.
Sexism isn't an isolated problem within tech community. Like many habits, it starts at home.
We take our sons to movies, where the hero chases a stranger, teases her, and finally they fall in love. This is almost a repeat in every single movie. At home, we scold our daughters if they laugh out loud, but our sons have a different parameter. They can tease any age female, whether known or stranger. That is not only accepted, in some cases even encouraged. We term it as forthcoming and an extrovert nature.
Then we are surprised, when they demonstrate that same attitude and behavior outside of home - office, society.
These discussions are useless without an action. Are you ready to stop watching movies with sexism is encouraged (same goes for castism or anything else that you care about. Not everyone has to care about everything)? Or encourage equality for gals in your group (family, office).
Show, don't tell. Start with the man in the mirror. Healing of the world starts with you, me, and us. We are the world we make.
You can make the difference. Let me tell you what I've done. I am not saying this to boast. I'm sharing with a hope that one of this will trigger an idea for one of you.
When Reuben Fernandez was stabbed by thugs because he defended girls from eve-teasers (in 2011), I decided I won't watch movies which promote eve-teasing. And I won't take my kids to those movies either. This has meant almost no movies for me and my kids.
While my entire family and everyone I know has cast identity as their last name, I dropped cast name. I was young when I did that (17). My father was livid, but I stayed with that decision. I did that after reading someone in my town shot dead during cast based riot.
My kids carry my wife's name, not mine. I have taught them why. So whenever they are asked about their name, they share about the reason. I hope they grow up to respect women.
Are you bothered about sexism? Then do something within your circle of influence.