A large portion doesn't use toilets and these groups intersect. What you eat is personal not a multiparty negotiation.

I believe that is what I am saying ?

What you eat is personal - having an impact on emissions/environment is not solved at a personal level, it requires nation level negotiations.

What you eat is at best a signal to higher level political groups of your inclinations.

Habits are not always preferences.

Political groups are lazy and/or inept and will assume such.

It most certainly is a multiparty negotiation. You eat things that can be reasonably obtained from vendors in your area, who in turn stock things they think they can sell. You order from the items available at the establishments you visit with your friends and family, who have input into where you go. You recommend foods to others, and eat foods that others recommend to you. In short, eating is a cultural activity you participate in.

As far as veganism is concerned, it is notable that it is much easier to be vegan now than 20 or even 10 years ago, as vegan ingredients are more widespread and higher quality, and "vegan options" are essentially standard in restaurants. This didn't happen through legislation, but by the application of social pressure by vegans - if vegans can't eat at your restaurant, they won't just go somewhere else, they'll take their friends with them. It is the output of a massive multiparty negotiation.