These Monsters' flawed logic.
To be iconic, something has to stand the test of time. By saying the meat dress is more iconic because it's more recent contradicts that.
Also, by that logic you could say that Single Ladies is more iconic than Thriller (as an example).
I don't really consider the meat dress all that iconic either (at least not at the moment). It's infamous if anything and may be forgotten after Gaga's career dies down, who knows.