How come people [here on Fluther] like to talk/debate/argue so much about things they don't understand or don't have a clue about?

When I was picturing this question I was thinking about the abundance of atheists around who like to talk so much about Christianity. I mean let’s be serious for a second. They only know what others told them. Most at some point read about it and didn’t pay attention to what they were reading and they only remember glimpses and use that as facts. Most don’t have a clue about what actually being a Christian means and they expect us to act according to what they think it’s correct.

But when I was pondering other things came to my mind. When someone asks a presumptive question then likes to fight about particularities for that situation yet they haven’t been through similar situations.
Or when a question is asked about a current event I saw a lot of people getting really aggressive or rude if your opinion differs from theirs.

What’s the deal?

Remember that not all do this but I personally witnessed a lot of these situations lately.

Feel free not to ridicule my grammar/vocabulary. Use a PM for this.

This is in General.