Stop complaining about the fodder using Earth Style...
Honestly, it has been a fact that ninja are not limited to their affinity for a while. Affinity makes it easier to master/learn that element, but does not actually limit you that element.
"This affinity makes it easier to learn how to create and control the nature in question, although even with an affinity this process will usually take any number of years. Shinobi are not limited to the nature they have an affinity to, though. By the time they reach the rank of jōnin, most shinobi have mastered two natures.
Because of the difficulty of mastering a nature and the time required to learn it, it is almost impossible for any one person to master all five natures through natural methods. However, those who possess the Rinnegan or Bashōsen can use all five elements, while Kakuzu got them by stealing other people's hearts."
Why is it that people scream plot-hole because of their ignorance?