I agree with your first paragraph. I don't eat with other people often but if a shop asked me not to talk when being with someone else I would just go elsewhere. Also I suspect the writer of the article put lot of efforts searching for such a shop because the only place I ever saw with the mokushoku policy is one of the university cafeteria and people (including me) don't follow it anyway. There is also a lot of plastic, which is useless but in line of the Japanese mentality of doing things for the sake of doing them instead of the impact it has on the output.