This whole debate is one big straw-man. I'm a vegan. I don't need burgers. I might want burgers, but they don't form a part of a standard diet just in the same way any kind of burger probably shouldn't form part of anybody's regular diet.
If you're eating processed food - there's a considerable chance that whatever it is you're eating - vegan or otherwise - is neither nutritious nor healthy. It probably tastes good though, which is why you want it in the first place.
Ultimately it boils down to this: if I'm eating a burger, then nutrition and health are more or less irrelevant - I'm after taste. I think the lives of animals are more important than my taste-buds, so I eat plant-based burgers. It's not really any more complicated than that.