Who are "ex-Muslims"?

A faction from among the People of the Book say: "Believe in what has been sent down to those who believe at the outset of the day, and towards the end of it disbelieve--so they will turn back [from their religion]. Believe only in someone who follows your own religion." SAY: "Guidance [means] guidance from God." No person will be given the same as what you (all) have been given, otherwise they would argue with you before your Lord." SAY: "Bounty [rests] in God's hand. He gives it to anyone He wishes; God is Boundless, Aware. He claims anyone He wishes for His mercy; God possesses tremendous Bounty!"

These verses talk about a popular trick that the enemies of Islam still use. You hear someone popular becoming Muslim, only to return back to his own religion after a month or two, or a year. In this way they dishearten new Muslims, and make other non-Muslims think Islam is not worth converting to since this and that entered and left.

But who really are "ex-Muslims?

1. People who were paid to enter and leave.
2. People who have a Muslim heritage but barely know anything about Islam, and they dislike what they know. It is easy for anti-Muslim organisations to pick these people up, give them media coverage, and lure them to other faiths or non-faiths with the promise of money and fame.
3. The third type is one that I heard about a lot in Iraq. There were some foreign religious organizations who gave monthly allowances to those who converted to Christianity for example. Most of the people were from the rural areas who, like the second group, barely knew anything about Islam.
4. People who converted without knowing much about Islam and when they found out the rules they didn't like them.
5. Fictional people.

There are some "ex-Muslim" websites and blogs on the internet. They write heart-breaking lies about Islam and quote mysterious "ex-Muslims" saying why they left Islam. I read a few of thse and saw that they were hooking up with the 2nd group of people I described. My guess is they are paid to talk badly of Islam.