The original poster wasn't attacking vegetarians as human beings, he was critiquing vegetarianism as a lifestyle and trying to open up a discussion about it. I don't see what's wrong with that. Without debate between two people, exchange of information cannot take place, and one cannot learn or grow. Where would we be if everyone just agreed with each other all the time? Debate is a valid format for expression of ideas, and often proves productive.

If you disagree with the original posters sentiments, that's perfectly fine. I happen to disagree with using religion as a basis to support something that's best established by repeatable science myself, and therefore I am less interested in the choice to eat meat from a moral perspective. However, you seem to be implying that the original poster was some how trying to attack vegetarians by expressing his criticisms of the moral choice not to eat meat. I don't see it that way. If someone expresses their criticisms of a low carbohydrate diet, I don't take it as a personal attack. I certainly may disagree with them, I may even regard them as ignorant, but criticizing atkins is not criticizing me.

Now, on the other hand, if someone were saying negative things about people who go on low carbohydrate diets (i.e. they are all fat idiots who want to eat a bowl of bacon instead of control themselves!!!), that would be a personal insult, just as would it be a personal insult if someone said something bad about people who choose to be vegetarian.