You’re saying that trying to motivate people positively to move on from meat is “push the blame away” behavior. But I think tut-tutting individuals who eat meat is pushing the blame away.
While there are some people who believe that eating meat is an absolute moral wrong no matter where or when it takes place in human history, a lot of people who feel eating meat is immoral feel this way because of what the meat industry does, both to the animals and to the planet. Five thousand years ago, people weren’t supporting the meat industry and all its wrongs by eating meat.
So considering it to be pathetic to try to effect real reduction in people’s meat consumption because the methods shift blame away from the individual meat eater seems really ironic to me, as well as completely counterproductive, if your goal is less meat consumption in the world.