The two most effective legal things you can do to help with climate are eating vegan and not having children.
According to Wynes et al. 2017 PDF (graph), while it's true that not having children is by far the best thing to try to prevent the anthropogenic climate cascade, veganism is only the 6th most important thing.
Being:
- car-free,
- flight-free, and
- fossil-fuel free for energy,
are all more important than being vegan.
When not just looking at anthropogenic climate, but ethical living overall; then yes, veganism is the 2nd most important thing after being child-free, because animal husbandry and fishing result in the torturing to death of 2-6 trillion fish per year, and on factory farms the enslavement in torturous conditions of 1-3 trillion fish and billions of non-aquatic animals every year.
I think it's to make you spend more time in the stores, see more products, and spend more money.
It probably works on most people, but there's such a small number of ethical products I buy, that it just reminds me how sociopathic these omnicidal capitalists are and that I should try to buy less things.