I personally don't have a problem with the raising and slaughtering of animals for food, but I believe there are better, more humanitarian, and more sustainable ways to do so than the current system. You could say I love eating meat, but would like to do so responsibly. I see a largely vegetarian diet as a means of commenting on said system, and by choosing to eat meat when I do eat meat that is locally and sustainably grown I am supporting a system I agree with. Many of the major issues I have with CAFOs can be dealt with by simply eating local meat. Where I live, this isn't hard to do; I live in a town surrounded by agriculture and a town that has joined the local foods movement with gusto. Just this morning, at the Saturday farmer's market, I passed a stand offering corn-fed beef and another offering chickens of various sizes. In the summer, there is also a sausage stand.
I understand many people in this country do not live in a place where meat raised outside of CAFOs is easy to come by, and I understand a vegetarian diet isn't practical for some; I myself am not a vegetarian and could never, ever be one. I like steak. A lot. But it is worth trying to eat less meat if you want to attempt to change the current system. Plus, it is healthier and cheaper. Economically speaking, eating a more vegetarian diet is a great choice.
I understand your frustration with overzealous vegetarians; given where I live (it's kind of a hippie town) I've met more than my fair share. Militant vegans are even worse
I think that sort of attitude has kind of motivated me to keep eating meat, but to make better choices about the meat I eat. Funny how their urgency to convert me has just backfired, huh?
The fact is, we could raise a lot more food for people on land we are currently using to raise food for animals in CAFOs. We have available rangeland that isn't being used because of the way the current system is set up, rangeland that couldn't be used to grow crops, but can be used for stock. Were cows in these places instead of in feedlots, this would free up some of that land we're using to grow cow corn to grow crops for human consumption.
The food system in the United States is fraught with problems; the meat issue is just the tip of the iceberg. We've addressed the issues of industrial corn and soy elsewhere on the forum. I'd recommend reading some Michael Pollan if you'd like more information.