I try to cut pig products out of my diet because I can't kick this comment someone said to me once, "Pigs. As close to eating humans as you'll get".

I know many humans who are not very social. Is "very social" a prerequisite for right to live?

No, it's a proxy for intelligence and higher forms of conscious awareness. There's no such thing as right to live for non-humans - if the world stops eating pigs, how many do you think would be alive? That applies in nature too where survival comes down to fitness and luck. But the higher the life form, the more human-like it is and the more humanely we should treat them. Ants get different dispensation from cows, and cows from dogs. Dolphins and elephants should get better treatment still, but this is not currently the case.