Gatekeeping what can be a burger or not is strange. Are you randomly ordering burgers and expecting a single recipe? What about those with chicken or fish in them, they also don't match the original recipe, which means you have to inform yourself about what's inside a given burger if you want a specific one anyway.

What about Coconut milk? Peanut butter? Do you think we should change their names too?

"Veggie burger" is a pretty well defined term at this point.