I think the main problem is that Muslim majority countries have not been able to erase the effects of colonization era, and are not developed. Branding Islam as a death cult religion is of course wrong, but extremist terrorism is directly related to the fact that muslim countries are not developed. You should look at the ratios of other crimes such as rape, thievery and corruption too. You will see that they have a higher percentage Muslim majority countries. I believe it is because of these two facts :
1. As those countries are not developed as much as European countries, they are not offering a decent education. Being a Turkish myself, (and Turkey is supposed to be one of the most developed of middle east) I witnessed an average of 3 points scored in our National Natural Sciences exam which consisted of 40 points. This is a huge failure. This is only the scientific education part. What of education of ethics, manners and other stuff? You can only observe its results. Uneducated, ignorant and hateful people.
2. Second reason is the fact that criminals are getting away from justice unlike well developed countries and that there is not an awareness of crimes in muslim countries as it is in well-developed ones. For example in rape cases, the rapists get away and even sometimes get themselves married to the victims. Many thieves are thieves because they are getting away with it. A serial killer in Turkey has been in hiding for two years. We just caught him. And what of corruption cases? Are these crimes Islamic? No, but they are done by muslims. It is an important fact.
So why there are Islamic terrorists but no christian or jew terrorists like ISIS and Al-Qaeda? Because people of christian and jew geography get decent education and have an awareness on crimes. I can never view a christian or jew as a threat, and I can only respect them, but I know that if they were given the same circumstances as current muslim countries, at least one in a million of them would be a part of extremist groups, committing such atrocities. My point is, religions are not the reason, it is in the very nature of humans. This difference exists because of a difference in conditions for people of different religions.
I can not believe how you can be like "I know quran better than billions of muslims and I did not even get a proper Islamic education, it is a death cult religion!". This was not the way I imagined you people. Whatever.
Long story short, Islamophobia is bad, but it can not be the reason why extremism exists in muslims, many other factors caused it, mainly focused on the fact that muslim countries are not well-developed.