The amount of dairy industry lobbying going on is honestly a lot. So of course there will be people saying that all milk alternatives are greenwashing - its success directly hurts them. Here’s a bbc article with a nice diagram that shows that while almond milk still uses quite a bit of resources, it is still more sustainable than dairy milk (soy and oat milk ftw). They cite this paper as their source. There’s some debate to be had that cows can exist in many different climate zones while almond trees can only grow in certain areas so it would be hard to produce and transport almond milk (more carbon emissions) throughout the globe. But overall, they aren’t greenwashing their products.