Ignorance. They know nothing about it and that allows people to fill the gaps in their knowledge with whatever bias they have. It's also true that all people hear about are Islamic terrorists. Obviously the jihadists represent a very small number of Muslims.
I agree with you. This is so true. People are usually unaware and in oblivion of what is going on. Most people are prejudicial and just assume what the whole community will be like by hearing about nonsense stereotypes which is really sad . The solution to this probblem is by education and respect and appreciation of other people's principles and cultures.