Well I have some thoughts about that too (also bullied as a kid).
First, I'm not entirely convinced a constant interventionalist policy as a parent is a good idea. I'm going to use the example of...homework. My parents nagged me to work on my homework, kept tabs on what my homework schedule looked like well into university, and partially as a result I felt very weak on time management for a very long time. Someone else I knew, who was very smart, had parents telling the teacher he didn't need to do particular homework assignments because they were "beneath him and he was studying calculus at home." That kid hit a wall sometime around high school when he did need to start doing actual homework, and it kicked his ass. Handholding and parental intervention is not always the best way to raise a kid. I agree that retrospectively, in this case, it probably would have been the right move, but hindsight is 20-20. Especially for a parent who is probably a socially inept nerd herself, just like the rest of us computer nerds, and so did not instantly figure out the right response to a non-obvious social situation.
Second, there's no guarantee that parental intervention will necessarily get a response from teachers. Cause my parents did intervene, a lot. Only decades later did I hear that my mother was usually dismissed, and told things like "don't you think you're a smother mother?" Teachers tend to think they know better (and in a number of cases they actually do). My father had a bit more luck, because he was a university professor, and was able to say things like "well, at the university when we have students with special needs, we do X". Although, honestly, neither of them were ultimately able to get the teachers to properly control the class, including not preventing violent bullying against me.
I dunno, to use an example that actually happened to a friend of mine, there was a high school in Vancouver. This school cared about getting a high score on standardized tests in order to attract more students. So...they encouraged lots students to drop out of math (to get a higher average). And my friend did drop out under such pressure. And my friend's father was pissed, and went on a years long campaign to get the school to change its policy. I have a lot of respect for my friend's father, and feel he went further and cared more about the issue than the parents of hundreds of other students affected by the policy. Yes, sure, theoretically my friend's father could have been some kind of superparent, figured out that the school had shady policies before they became a problem for his kid. But seriously? No, my friend's father is an absolutely fantastic parent for whom I have tons of admiration.
Bottom line, as a parent you have to trust schools and let them operate in their own way at some level, especially when you're a working parent frequently on the road. But even if you're a stay at home parent, the school won't let you have more than a certain amount of influence. And when you trust schools you make certain assumptions about professionalism, like "a school would never encourage kids to drop out of math" and "surely, a school will recognize the problems that could arise when there is only one girl in a computer class, and would step in if things got out of hand."
Remember, if you actually go to parent teacher night, or write letters to the school, you're still putting in more participation and oversight than 80% of parents.
