Let us try to understand why Islam is considered a religion of violence.
Today is the age of media. Before the advent of the modern media there were a large number of people in the world who knew nothing of Islam. With the invention of the printing press and the advent of the electronic media it is difficult to find even a single person, today, who is unaware of it.
But there is a clear-cut difference. In previous ages it happened that wherever Islam spread people were so impressed with it that most of them welcomed it. Strangely enough though, the present day coverage given to Islam has produced only a negative effect due to the negative actions of certain Muslims. People are now generally allergic to Islam rather than being interested in it.
Why are certain Muslims behaving negatively? According to Maulana Wahiduddin Khan, this is due to not knowing the limit of freedom. Modern man aspired to freedom as the highest good, but once having reached this goal, he was unable to set reasonable limits to freedom. In consequence, unrestrained freedom descended into anarchy and lawlessness and all other forms of negativity. Unrest starts at the level of the mind. This happens when people become conditioned to living lives, which are self-oriented instead of God-oriented. As a result of this unrest, they either live in a state of insecurity or isolate themselves from society, or in other ways become negative in their reactions. Some go to the extent of taking the law into their own hands, which results in chaos, violence and even global terrorism.
The tragedy of all is that in actuality, it is no exaggeration to say that Islam and violence are contradictory to each other. The concept of Islamic violence is so obviously unfounded that prima facie it stands rejected. The fact that violence is not sustainable in the present world is sufficient indication that violence as a principle is quite alien to the scheme of things in Islam. Islam claims to be an eternal religion and, as such, could never afford to uphold any principle, which could not stand up to the test of time. Any attempt to bracket violence with Islam amounts, therefore, to casting doubt upon the very eternity of the Islamic religion. Islamic terrorism is a contradiction in terms, much like 'pacifist' terrorism. And the truth of the matter is that, all the teachings of Islam are based directly or indirectly on the principle of peace."
Source: The Age of Peace