No, it's a demonstration of ignorance. LaTeX wasn't written by Lispers, it is merely used by them. The fact that they find its design decisions acceptable must be weighed against the cost of their alternatives. That doesn't imply that they wouldn't have been happier with a more lispish syntax.
At the time that those decisions were made, LaTeX was pretty much the best alternative. The fact that Lispers, like almost everyone else in related communities, made that decision merely says that Lispers don't cut off their noses to spite their face.