How Can the Gospels be both Copied and Contradictory?

I've been trying to read more Christian blogs lately in an effort to branch out a little bit, I certainly don't want to live inside a bubble of my own making. As a result I have been coming across a fair number of apologetic arguments, which quite often aggravate me because of how ridiculous and stupid tend to be. This particular argument is bad enough that I would normally completely ignore it, except that I have seen it a few times in the last month. It is an attempt to make atheists look silly by asking how it is possible that the gospels can be contradictory and also be copied. Of course the answer is simple, there are parts of the gospels that are copied from each other and other parts that are contradictory. Nobody is claiming that the entirety of Mark (say) is an exact copy of Matthew, but that certain passages are copies of other passages.

What really bugs me about these kinds of claims is that the people making them know they are bullshit. Of course it is possible for a book to have copied passages as well as contradictory ones. But they don't care, they can straw man our arguments until they are unrecognizable and make fun of the result and their listeners will believe it is representative of what we say because they are trained to not question their leaders. They aren't supposed to think critically about things, they are supposed to have faith.

I think the real reason I have such a reaction to this kind of thing is because I know that when I was a kid/teenager I would have totally fallen for it. If my pastor or a religious person my parents were listening to on the radio said something, I'd believe it. Why not? They are men of God, I can trust them. If they say that atheists make these stupid arguments who am I to question it? Luckily I eventually grew up and realized that I had been lied to, but most people never do this for some reason. It's part of the reason I started writing this blog, I'd like to think if I had come across this type of writing when I was still a Christian I could have left the religion sooner.