You're saying that vegan people have to use milk alternatives like almond milk. Which is certainly not the case. What a non-argument.
Also, the problem with milk is not necessarily CO2 but CH4.
Also, the problem with milk is not necessarily CO2 but CH4.
For vegans it certainly is the case. Vegans don't eat food that comes from animals. Milk is one such product. So vegans will definitely use milk alternatives.
Also if you spill some somewhere your house doesn't smell like rotting bodily fluids (ok, probably getting a little extreme here but who likes the smell of rotting milk?)
Only downsides to plant milks, is they are harder to steam for lattes, they don't make cheese like we expect from animal milk (tho this has changed a lot and we're just about there now with some amazing brands), and they do have a unique flavor profile that is sometimes desired (for stuff like homemade egg nog for example).
Some people do drink almond milk of course, also meat eaters btw.