I'm not really sure what this article has to do with the US, but what you're talking about is not up to individual states in the long run.
>separation of state and church should still serve as a safe guard against introduction of any religious/politiacal topics.
How does separation of church and state prevent the introduction of political topics?
> Wwat they teach you in that subject is more or less common sense stuff
Most schools in the US have at least something similar, but how does that matter at all? Just because the US and Japan have something that could be called "moral education", it doesn't mean that something called "moral education" in Hong Kong would be similar.