Standing with us and denouncing the violence is enough, the only reason you'd be singled out as a Muslim is so few people know Muslims. I mean really know them, and appreciate that there's not a terrorist in every Mosque.
There's no sense of commonality or unity. The message of terrorism has spread far and wide. That is why you'd be asked that question and fear having no answer, our actions reflect our knowledge as determined by the media... so we're really extremely ignorant of Muslims and knowing the truth of if "they" are the "enemy" or not.
ISIS is actually useful in this regard, for we can call them out by name and help avoid isolating good people in the process.
I whish the public would always separate between average civilians who's main concern is to make a decent living and their policy/decision makers in the other hand, and that's meant for both sides of the equation.
I think the Arabs must understand that the average western citizen doesn't care about which religion you believe in, who you worship, the matter of Palestine/Israel, or any other of our own problems. They just mind their own business, and atop of that they're out there to make a living, like any normal human being should do.
The same could be said for the opposite direction, we don't wakeup every day with goal to convert everybody else or try to backstab them for what is happening here in the region. The average Arabic/Muslim goal is the same actually; to have a decent life.
Why would or should anyone ask that question of you? If I was a Muslim and someone asked why the 9/11 attacks or Boston bombing occur my answer would be that these people were evil/had evil motives and were not acting in accordance with the teachings of Islam. And as a Muslim you do not support nor condone these actions as they're not in line with Islamic teachings.
Why on Earth would anyone expect you to have an answer for other people's actions? I've read the parts of the Quran and the haddith which require violence against infidels, homosexuals, etc. I've also read the parts of the Bible which require violence against infidels, homosexuals, etc. Would you expect me to explain why the Lord's Army is hacking people to death in Africa? An individual is responsible for his own actions, and a group of individuals are responsible for their own actions, but Islam and Christianity are each far too large to be monolithic. Yes, Islam is far more violent a religion than is Christianity, but that doesn't make you responsible for others' interpretations of it. You aren't any more a part of that "we" than if you happened to share a skin shade or an ethnicity with the culprits.
What worries me for example, the continuous rise of Islamic/Muslims hatred because of such crimes, which I understand it happened because particularly the so considered leading Islamic countries did nothing tangible to both denounce such acts and educate the new generations on how wrong they were as well.
Actually, I was surprised at the Friday-prayer preach right after Charlie Hebdo attacks, in which the subject wasn't mentioned at all like it doesn't concern us or we don't care. Actually, if we have the slightest piece of brain then we must do all what we could do, the least reason would be that to protect some millions of Muslims living out there from revenge incidents.
And here just to make it clear, of course we refuse the insult to the prophet, but if someone justifies killing for it, then he must seek some mentality hospital.
Nobody could deny our harsh part of some Islamic rules and believes and it's already there translated and easily obtainable by anybody to read it, yet I don't understand why no one ever from had tried to study and discuss the other and yet the largest part of total 600 pages of Quran.
Problem is, and I always will repeat it, reading by it's original native language is totally different than reading it's translation.