Another factor is relevance. Web related stuff has application in an environment that students are very familiar with.
Here I disagree. Learning programming is not about learning a language, its more about learning to choose the right language for the task and mastering it to the level you need. Whatever specific language you teach would probably be outdated by the time the kids reach the market.
I reckon that teaching programming in lower to middle secondary school is all about teaching thinking, logic and problem solving. Getting a feel for what programming is to see if it might have some career prospects for them is also good. I really don't care what language so long as it is accessible and the kids see some relevance. I'm not talking about relevance as being work ready.