A conflict between an American Christian and an American Muslim? What does that have to do with loyalty to the United States? I think you meant something different.
How do you define putting religion over citizenship? This is the United States, where you can practice any religion you wish, while at the same time you have the right to peaceably assemble and petition the government for a redress of grievances. Isn't that exactly what was happening in this case? Or are you suggesting that because they are Muslim Americans, that right doesn't belong to them?
This has nothing to do with loyalty or lack of it because of religious affiliation.
What is it that you see that makes you believe it is disloyal to encourage unity in a community and connect with its own religion? How could that possibly be a wrong thing? The Untied States is the ultimate melting pot, where there is the most diverse communities who are allowed this inalienable right. They create programs to help each other, help people who have no outside assistance. Communities that advocate helping each other in times of need, communities that look out for their own people to help those who might need help. In Muslim communities there are assistance programs to help those who can't afford emergency health care, who have an ill person in the family who's family needs help until he gets better, or even raise funds so they can make the pilgrimage to Mecca. Assistance for Muslim refugees around the world. Syrian refugees, Palestinians etc. Assistance to help with burials if someone has passed away and they can't afford it, etc. This is not something you see just in Muslim communities. It happens with all sorts of Christian denominations through their churches throughout the entire country. It happens within communities of certain nationalities, like Brazilians, many other South Americans, Vietnamese, Chinese, Indians/Hindus and the list goes on.
Jewish communities are quite actively dominant in that regard, and they suffer considerable prejudices as well.
All these communities experience some form of prejudice or another and speak out because of it. So why are we especially singling out Muslim communities in this case?