that is an excerpt from the old testament before Jesus came and died for our sins , before this, in the old testament, there were many similar punishments that would be considered severe. However because Jesus died for our sins if we believe in him and ask for forgiveness we are forgiven . but yes when i first read that verse i thought it was a little harsh too , good thing we don't live in those times lol.

mandatory study of the bible exclusively ? no but study of Christianity and many other religions including history of the religion , beliefs, and such ? yes . you cant force someone to believe in something in does not work, it only produces a resentment twords it. education on religion in general is important though.

the debate over weather Islam is a violent religion vs. the people who practice the faith are a violent people are two entirely different things. Are there more extremists who practice Islam in comparison to other religions such as Christianity or Judaism ? perhaps but that is not to say that the religion of Islam itself is violent in nature. in fact the principals of the faith are not very different compared to Christianity, in fact they even regard Jesus as a prophet , as well as Moses and many others, they simply believe that Mohammad is the most recent of prophets, that in actuality is the biggest difference between the two.