He doesn't say it's a Muslim country. He is talking about his views, as a US citizen of Muslim faith, about terrorism in the name of Islam. He condemns it and says that him and others like him want to keep it safe. US citizens of Muslim faith have every right to call this country their own. As do all the other people that came here in last 300 years. Its their country too. That's the reason he is speaking against Trump in the first place. Because people like Trump don't seem to understand that.