Islam & Iran

I am muslim , but I am not from Iran. I just saw a video about Iran and its heritage. Lions used to be symbols of Iran, but they are no longer officially used. I've seen a lot of Iranian people immigrate to europe Iran is just consuming its economy to go into wars under the name of Islam. I've also seen a lot of atheists from Iran, yet the government runs the country under the name of Islam, which I do not get. Like, Islam seems to have not been accepted since the beginning are all Iranian people against their government or what , i do not mean being rude but just curious