Really, Penny Press? You think a taco is a sandwich? Well I have news. Tacos (also known in some circles as Mexican tilties) are not sandwiches. A taco is its own distinct category of foodstuff. To think otherwise is insanity.
If a taco is a sandwich, then surely a hot dog is a sandwich as well. Under this twisted logic, a burrito would also count as a sandwich. At that point, why not just call everything a sandwich? How far does the rabbit hole go?
It is important to set boundaries, otherwise the word sandwich loses all meaning. A taco is a taco. A is A. End of story.