These things are not reported but somehow magically I know and other people don't.

It's not that the media is denying it, it's reported on. It's just that most American's couldn't care less, which is the point. So you won't see it on CNN.

Usually foreign affairs are not reported on in western media (by "not reported on" I mean not on the front page of reddit or on cable news, of course you can find it with Google) because it's not relevant to most people. The only reason we hear about Christians being persecuted is that there are lots of Christians in western countries and they care when other Christians are persecuted.

So let's say Americans are murdering people in cold blood. Is it because of Christianity?

No, people never kill or terrorize because of religion, they do so for political reasons. Religion is a tool, not a cause. The Middle East produces terrorists because the region is in turmoil, people feel humiliated by, afraid of and angry at western powers who are responsible for that, and these sentiments manifest themselves as Islamic terrorism.