You are free to call it whatever.

I am without allegiances.

Bees aren't plants.

More seriously, if they follow a nearly vegan diet for ethical reasons, except they don't give a shit about bees, it makes sense to describe their choice as approximately vegan, rather than plant based, because it is approximately vegan.

Because most people to this day don't know what the hell "plant-based" means. Products in the market often dilute this term too, unfortunately.