Because complaints about vegetarians aren't directed at people like Beggs and B but organizations like PETA and the individuals who promote such organizations. Beggs and B take exception to the complaint that a great many vegetarians are by and large claiming moral superiority. Beggs writes:
"because for some reason it's hard for some people not to take it personally. A certain kind of person - and it's not a rare kind - seems to take it as a personal slight."
The reason "it's hard not to take it personally" when vegetarians go on about their vegetarianism is because it is intended to be personal whether Mike thinks so or not. PETA absolutely is claiming moral superiority over non-vegetarians. When vegetarians go on about the need to reduce suffering they absolutely are seeking to impose their preference upon others.
If ravi doesn't want to eat meat I could not care less but if he imagines that suffering anywhere in the world is reduced by his individual consumption choice he is fooling himself. If he believes that his individual choice reduces suffering then by extension he believes that if I stopped eating meat suffering (however ill defined) would decrease as well. If I stopped eating meat tomorrow or if I died tomorrow the amount of suffering in this world would not be affected in the slightest. If PETA could drop the moral condemnation of all meat eaters and instead focus on improving the conditions of animals used for food stocks that would be great. Hell, I'd offer my time and money to support their cause. But they do not intend to do that. They instead seek to impose a meatless morally superior world-view on everyone else. Fuck that.
John Thornton