Extremists of any ilk are always problematical. *G*
The "bible thumpers" as you (and I, not to their faces, because I have manners aka necessary social hypocrisy) call them ARE no doubt part of the problem many people have with Christianity.
Do you know anyone who enjoys being told they're bad and unworthy most of the time or being treated as though they are? Even my dog hates it.
But, you can use ANYTHING to look down on others if you're so inclined. My husband and I had this conversation in the car the other day, as we have slightly different political persuasions. He's a bit more liberal than I am in some ways..not socially, but politically...he's so liberal, he makes Obama look conservative. I think part of that is reactionary...he just hates seeing people suffer. He can't even watch my dogs cry when they get their toenails cut. When the kids have skinned knees, he get frantic.
Anyway, I jokingly called him a "dirty liberal" and he laughed and said, "I'm glad you noticed." but it led to us discussing how people will use that to look down on each other. To a conservative, a liberal becomes "a bleeding heart pussy pinko" and to a liberal, a conservative is a "tight assed heartless tea bagging idiot" and on and on.
But, it occurred to me that people will do that with anything. To the fundies, I'm sure more tolerant liberal and non literalist Christians like myself, a UU is barely Christian, if you think Christianity is defined by defining morality strictly and the Bible literally.
(I always think of that bit on the Simpsons where the Flander's kids are playing a "Christian" video game where you get points for converting non-Evangelicals/Fundies by shooting them with little bibles, and the kid says, "Dad what do we do about Unitarians...do they count?" and he thinks a minute and says, "You get half the points."LOL)
But, I will say that it's easier for a tolerant Christian to bear the intolerant variety, most of the time. Fundamentalism by it's very nature is non-tolerant and divisive.
Which seems unnecessary to me, but I'm not sure that Jesus meant that exact thing when he said that Christianity would divide people and even households.
In context, he was talking to Jews, and Jews already knew what it was like to be divided from the rest of humanity by virtue of unique belief, so why belabor the point?
Did he mean that anyone who decided to follow his words would seem "odd" to others? That's how Witnesses interpret that, at least, to some extent.
I'm sure that Christ was speaking of the POSSIBILITY that some would interpret his teachings in an intolerant fashion, because hey, ,some people are like that. I'm not sure that means it's a necessity to be intolerant or at odds with everyone to be Christian.