Let's break down your comment sentence by sentence:
"Muslims in the United States have proven themselves to be loyal to their country and politically moderate."
WRONG. In fact, you know a guy named Lewis Farrakan? He is the leader of the "Nation of Islam" (NOI) movement. The majority members whom are black. Wanna take a guess which ethnic group in the United States practices Islam...African Americans (or Blacks). Most blacks are not right leaning and most have liberal/socialist mindsets, therefore not a part of the capitalist system run by the conservative Christians. For the blacks who are socialist and Christian, Jesse Jackson is their leader. Make note that Farrakan and Jackson are buddy buddy for a reason.
"But around the world, especially in Europe, Islam is increasingly viewed as a danger, and young Muslims as unpatriotic."
Islam in fact OUTSIDE the United States is viewed as moderate, especially in Europe and Asia since Muslims are seen as running from a occupier of their lands, Israel. Muslims are only viewed as unpatriotic to ISRAEL. Considering when the Israeli Defense Force (IDF) routinely kills and tortures Muslims for fun, even when they are born inside Israel and are actual Israeli citizens.
"Is this an appropriate bias in dangerous times, or is it bigotry? And what makes the United States different?"
If you are referring to what makes the US different from Europe, is it (BOTH political parties) and Israel are attempting to remove Islam from the middle east. For some odd reason the Christians seem to think the Jews own all of the middle east and have been trying for almost 1,100 years to get it back for them, but without success. Now that modern warfare as been developed and World War I brought down the Ottoman Empire, they are now moving forward with genocide of Muslims.
Why does this bother Farrakan and Jesse Jackson? Because Americans are the stupid group of sheep on earth and after the next false flag terror attack carried out by the government/Israel, people will "demand" that the Muslims be rounded up and put into camps. What do you think will happen when the US government attempts to put every BLACK man, woman, and child into a camp. Oh damn buddy. Gonna be fun to watch.