I saw some Indians on TV worshipping rats and cows. Does your religion approve this?
Also, I've seen extremely inhumane practices by Chinese buddhists, is this buddhism?
What if I saw some religious Christian from the KKK kill a black guy, or a Christian Norwegian terrorist killing children, is this Christianity?
Its ridiculous if not offensive to even ask such things. Theres 1.7 billion Muslims of all kinds and sorts like all humans. Some smart, some not so smart, some ignorant, some educated and knowledgable, some extreme, some moderate, some lenient.
Choosing something that some guy did (if proved to be true) in a country that has been in Chaos, war, and starvation, for decades, and has one of the highest illiteracy rates in the world, and then suddenly wondering if this "example", of all in the world, is Islamic or not, just doesn't make me think its a sincere question.
Why not ask about a Muslim leading NASA scientists like Farooq al Baz? At least he has some credibility although not a religious figure.
Anyhow, I know nothing about the video you saw, but in Saudi Arabia for instance, those who try to smuggle heroin into the country, and those who rape/kill women and children, are executed "mercilessly" with one strong strike of the sword to the neck. Other countries hang them.
Due to the nature of such horrendous crimes, I think their execution is certainly justified, and that the method is much better than using electric chairs, and much better than letting the child killer go free after no more than a decade which might happen to the Norwegian terrorist who targeted kids at school.