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It may be due to different understanding of levels of devotion. My personal cut-off is where you put your religion ahead of society and the self fulfillment of others.
For example, academic work shows that the majority of Muslims in Wien places Islam above Austrian law. The Muslim community also has the highest fertility rate. Meaning that using public funds that meant to support childbearing, the Muslim community will overgrow the natives and eventually force Islam on them. This is not Islamophobia, this the outcome of the current trends to our best of our knowledge.
It becomes Islamophobia when you lay the blame on personal Humans that happen to be Muslims. As it’s not 100% of Muslims, but around 55-75% (depends on the work).
First generation of immigrants are usually cool people.
Problem starts when the second doesn’t integrate well into society and tries hard to connect with their other cultural background. When that other background is Islam, they become extremists Muslims.