He's being a fucking idiot.
I had an uncle who made the point that "plants feel pain/it's killing a life so I'm not going vegan". He kept guilt tripping me about it and then I looked into the Fruitarian diet and told them he doesn't even have to kill plants if he wanted to.
Next thing he says: "You're eating microbacteria so you're still killing life so it's okay I'm not vegan."
He's mentally a sick person. I'm still a bit upset, because for those weeks he was living with me, it felt as if I was starting to have a legit Eating Disorder because of this dumbass. I almost stopped eating and felt fucking disgusting each time I even looked at fucking bread.
Don't let him guilt trip you into believing that everything you're doing is causing suffering. It's going to cause straight up mental health issues.