I went to Stuyvesant HS 10 years ago, and I took all the CS classes that the school had offered from Mr. Zamansky ("Z", as we affectionately call him), and can add some more specific information as to why this was necessary.
Stuyvesant opened in the beginning of the 20th century, and there are some vestigial components that should've been amputated long ago: in addition to the standard math, science, language (English and foreign), gym requirements, it has some requirements that truly made it historically a technical vocational school. To wit:
1 year of technical drafting (1 semester of drawing mechanical designs on paper, 1 semester of CAD), and 1.5 years of technical shop (1 semester of single-period shop, and 1 semester of double-period shop). By technical shop I mean the following: you get to choose two of ceramics, woodworking, metalworking (aka jewelry-making), electronics (aka computer tech), photography and video editing.
It's worth repeating: taking drafting and shop is required to graduate. By and large, these classes are not popular with students at all, the most obvious reason being "why the hell do we need to know this outdated shit? If someone likes it, they can take it as an elective."
Over the years, Z developed an ass-kicking CS curriculum: Intro to CS, AP CS (1 year), Systems/Network Programming, Graphics, and Independent Research. They are extraordinarily popular with the students, partially because Z is a great teacher, and partially because of the support of the previous alumni who would regularly take junior and senior-level college classes in their freshman college year thanks to that curriculum.
It's worth pointing out that none of the CS classes qualify for any graduation requirement. If you take them, you are taking them on your own time because you are interested. Aside from the knowledge itself, there's no carrot, even though the rest of the world is pointedly indicating that we need more software engineers and less metalworkers.
Now, Z goes to the current school administration and says "hey, can we add CS as an option to fulfill some graduation requirements?" and for 10 years straight (not kidding) the response he was getting was a consistent "GFY". Welcome to the NYC public school bureaucracy and people defending their own turf. It's not even that he asked anything outrageous. He didn't say "Hey, can we get rid of drafting and shop?". He said "Can we give our students more choice as to what is required to graduate?"
So, about two years ago Z decided to try a different avenue - working within the structure of Stuyvesant was not feasible, so he might as well go outside of it. Someone I know connected him to Fred Wilson, they chatted, and the rest is what you see in front of you. None of this would've happened if the Stuy HS administration had a few less heads up their asses.