Green brown and other camouflage colors,

These colors protect the soldiers, (Personification)

As someone would protect his brothers. (Simile)

Always carrying weapons they are prepared for any disaster,

They can be as powerful as a blaster (Simile/Hyperbole).

They are here to protect us, giving their hearts to the people (Metaphor)

And with the symbols of the uniform representing that they will fight against evil. (Symbolism/Metonymy)

With the banner of the USA on their chests,

They represent that as an army they are the bests (Symbolism)