1) How did the Islam religion that seems to be similar to other religions become scary and deemed as terrorism/evil?
A: Extremist groups. The Quran does have lines that say followers must convert people to Islam or they should die. The five pillars may have been shooed off and instead, evil Quran lines have been more prominent. (I have read them myself).
2) How did the Islamic religion now become a religion of violence?
A: Fundamental Muslims that interpret the Quran more literally and for what it says (the violent lines).
3) Why don’t we see or hear more about mainstream Muslims?
A: They are threatened and fearful of others who disagree with their interpretations.