In all of those roles, I have almost never experienced anything that I would classify as sexism. If I were to rate each experience according to how big of a role gender played in the attitude of the people around me, working in a technology company as a developer would win out head and shoulders above the rest.
Here's the thing.
The technology industry is a meritocracy. Geeks don't care where you were born, if you wear a suit or a scruffy tee shirt, what your orientation is, what you look like, and they barely notice if you happen to be female. Geeks care if you are smart, capable, and can make cool shit. Everything else is background noise. The men (and women) that I have known in technology make up one of the most consistently gender neutral cultures I have ever encountered.
I think that one of the reasons working in technology is difficult for many women is the simple challenge of feeling different. Anytime that you are different from everyone around you it is a challenge. You will run into places where the defaults just don't work for you. You will have to do more work to find solutions to problems no one else has. When your fundamental perspective diverges from the people around you, you have to work harder to communicate and understand ideas. At best, it's a lot more work. At worst, you may feel like you don't belong, worry that people don't accept you, or wonder if there is something wrong with you.
Me? Feeling different is comfortable territory. The skills for navigating a foreign environment, carving out my own place, and the ongoing extra effort involved all come second nature to me. Honestly, I don't even know what it would be like to "fit in".
I do know what it is like to be dismissed and looked down upon for being different, something I have seen in spades as a bisexual woman in the gay community, but not once as a female in technology.
I understand that my experience may not be representative of all industries, or even all technology companies.
But it bothers me deeply that women are being taught that they cannot succeed in technology. It offends me that they are told they will be oppressed and not taken seriously. And makes me angry to see women being trained to see every indication gender difference as a sign of prejudice.